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ELECTROTYPE  MANIPULATION. 

BEING 

THE  THEORY  AND  PLAIN  INSTRUCTIONS 

IN  THE  ART  OF 

WORKING  IN  METALS, 

BY 

PRECIPITATING  THEM  FROM  THEIR  SOLUTIONS, 
THROUGH  THE  AGENCY  OF 

GALVANIC  OR  VOLTAIC  ELECTRICITY. 

ALSO  IN  THE  ARTS  OF 

ELECTRO-PLATING,  ELECTRO-GILDING,  AND  ELECTRO-ETCHING; 

WITH  AN 

ACCOUNT  OF  THE  MODE  OF  DEPOSITING  METALLIC  OXIDES,  AND  OF 
THE  SEVERAL  APPLICATIONS  OF  ELECTROTYPE  IN  THE  ARTS, 

BY 

CHARLES  V.  WALKER, 

HONORARY  SECRETARY  TO  THE  LONDON  ELECTRICAL  SOCIETY;  EDITOR  OF 
THE  ELECTRICAL  MAGAZINE,  KTEMTZ'S  METEOROLOGY,  ETC. 
TELEGRAPH  ENGINEER,  AND  SUPERINTENDENT  TO  THE  SOUTH-EASTERN 
RAILWAY  COMPANY. 

ILLUSTRATED  BY  WOOD-CUTS. 

SECOND  AMERICAN, 
FROM  THE  TWENTY-FIFTH  ENGLISH  EDITION. 

PHILADELPHIA: 
HENRY    CAREY  EAIRD, 

SUCCESSOR  TO  E.  L.  CAREY. 

1852. 


GETTY  CENTER 


ELECTROTYPE  MANIPULATION! 

PART  I. 

BEING 

THE  THEORY  AND  PLAIN  INSTRUCTIONS 

IN  THE  ART  OF 

WORKING  IN  METALS, 

BY  PRECIPITATING  THEM  FROM  THEIR  SOLUTIONS, 
THROUGH  THE  AGENCY  OF 

GALVANIC  OR  VOLTAIC  ELECTRICITY. 
BY 

CHARLES  V.  WALKER, 

Honorary  Secretary  to  the  London  Electrical  Society ;  Editor  of  the  Electrical 
Magazine,  Ksemtz's  Meteorology,  etc.  etc. 
Telegraph  Engineer,  and  Superintendent  to  the  South-Eastern 
Railway  Company. 

ILLUSTRATED  BY  WOOD-CUTS. 
FROM  THE  TWENTY-FIFTH  ENGLISH  EDITION. 


PHILADELPHIA: 
HENRY   CAREY  BAIRD, 

SUCCESSOR  TO  E.  L.  CAREY. 

1852. 


PHILADELPHIA: 
K.  AND  P.  G.  COLLINS,  PRINTERS. 


PREFACE 

TO  THE  LATER  EDITIONS. 


The  rapid  sale  of  the  earlier  editions  of  this  work 
can  only  be  traced  to  the  great  popularity  of  the  subject 
on  which  it  treats. 

No  branch  of  Experimental  Philosophy  has  been  more 
cultivated  than  Electrotype.  Like  all,  it  is  replete  with 
interest,  whether  examined  in  its  theory  or  in  its  re- 
sults— unlike  some,  it  leaves  a  trace  of  its*  footsteps — 
a  tangible  evidence  of  its  power.  I  allude  not  to  its 
profitable  applications  in  the  hands  of  the  artisan; 
furnishing,  as  they  do,  a  full  and  forcible  reply  to  the 
oft-proposed  question :  "  What  is  the  use  of  Electricity?" 
For  him  these  pages  are  not  written ;  his  demands  upon 
the  art  are  of  another  nature,  and  are  intimately  con- 
nected with  his  own  resources.  I  write  for  him  who 
delights  to  devote  a  portion  of  his  hours  of  relaxation 
to  the  study  of  those  mysteries  of  nature,  into  which 
the  eye  of  science  has  been  able  in  a  degree  to  pene- 
trate.   It  may  be  safely  said,  that  in  the  length  and 

1* 


vi 


PREFACE. 


breadth  of  England,  the  proportion  of  such  individuals 
is  far  greater  than  elsewhere;  there  is  amongst  us  a 
national  love  of  home,  and  of  7iome-occupationsj  and 
when  we  do  wander,  we  feel  that  we  are  wanderers ;  and 
can  regard  with  pleasing  anticipation  the  time  which 
will  return  us  to  our  home.  Amongst  home  attractions 
is  ever  found  a  taste  for  the  fine  arts;  this  is  seen  even 
in  the  cottage,  whose  walls  are  adorned  with  "much  that 
taste,  untaught  and  unrestrained,  surveys  delighted;" 
the  inmate  of  the  humble  tenement,  "around  whose 
walls  are  heroes,  lovers,  kings,"  surveys  them  with  a 
satisfaction  closely  akin  to  that  which  animates  the  man 
of  cultivated  taste,  as  he  views  the  perfect  productions 
of  a  Raphael  or  a  Correggio.  This  taste  is  abundantly 
gratified  by  the  discovery  of  Electrotype;  it  enables 
each,  who  desires  it,  to  furnish  himself  with  durable 
copies  of  the  finest  productions  of  the  chisel  and  the 
graver.  He  finds  an  inexhaustible  field  open  before 
him;  and,  if  he  devote  his  time  to  forming  collections, 
he  is  animated  at  every  step  by  the  novelty  and  interest 
attached  to  each  fresh  acquisition.  And  not  the  least 
feature  of  interest  allied  to  a  collection  thus  formed,  is 
the  fact  that  every  specimen  is  stamped  with  a  double 
signature  of  "mine" — "mine"  it  is  by  possession — but 
especially  it  is  "mine"  by  production. 

When  I  consider  how  many  copies  of  this  treatise 
have,  during  the  last  year  or  two,  been  dispersed  through 
all  quarters  of  our  land  (and  not  ours  only),  I  cannot 
but  feel  that  it  has  been  in  some  measure  instrumental 
in  enabling  very  many  to  tread  the  same  pleasing  path 


PREFACE.  Vii 

that  I  have  trodden.  I  trust  my  endeavors  to  pave  the 
way  have  not  been  unsuccessful.  On  first  venturing 
along  the  new-discovered  road,  I  found  many  a  stumbling- 
stone  besetting  my  steps;  and  many  a  time  have  I  had 
to  survey  before  I  could  tell  which  track  would  lead  to 
the  desired  end.  These  obstacles  I  have  endeavored  to 
remove  from  the  path  of  those  who  are  interested  in 
following  the  traces  marked  out;  I  have,  too,  watched 
with  care  the  progress  made  by  others;  and  have  in 
each  successive  edition  embodied  as  much  fresh  informa- 
tion as  conveniently  I  could.  To  my  more  mature  ex- 
perience on  the  subject  of  mould-making;  to  the  general 
principles  on  which  the  reduction  of  metals  is  based; 
and  to  the  description  of  new  arrangements  of  apparatus 
which,  with  revisions  of  many  paragraphs,  were  given 
in  the  earlier  editions,  I  have,  in  this,  added  all  the  im- 
provements, up  to  the  present  time,  that  I  could  con- 
veniently compress  into  these  pages. 

It  was  at  first  my  intention*  to  have  added  observa- 
tions on  the  deposition  of  other  metals;  this,  however, 
was  not  found  possible;  there  was  so  much  to  be  said 
that  could  not  be  contained  within  the  present  pages, 
that  I  rather  determined  to  unfold  fully  the  principles 
and  practice  of  the  art  in  this  treatise,  and  to  prepare  a 
Second  Part,  to  be  devoted  to  plating,  gilding,  etch- 
ing, and  all  the  several  applications  of  the  art,  which, 
for  want  of  space,  could  not  be  introduced  here.  In 
Part  II.  will  also  be  found  the  etching  of  Daguerreotype 


*  Preface  to  Fifth  Edition. 


Vlll 


PREFACE. 


plates,  and  several  modifications  in  Voltaic  apparatus. 
In  the  Fourth  Edition  of  Part  II.,  Electro-Printing  is 
introduced;  and  the  process  of  plating  and  etching  are 
dwelt  upon  more  fully. 

CHAKLES  V.  WALKER. 

Westbourne,  August,  1844. 


PREFACE 

TO  THE  EIGHTEENTH  EDITION. 


To  the  former  Editions  of  this  little  Treatise  so  many 
additions  had  been  made,  that  the  arrangement  had  be- 
come somewhat  irregular.  In  preparing,  therefore,  the 
Sixteenth  Edition,  I  rearranged  the  whole,  rewrote 
many  parts,  and  added  several  interesting  facts  that 
recent  investigations  have  brought  to  light.  The  same 
are  continued  in  these  later  editions.* 

C.  V.  w. 

Tonbridge,  June,  1847. 


*  In  the  Twenty-first  Edition,  I  have  given  a  description  of 
Gutta  Percha  and  other  moulds,  and  in  the  Twenty-third  is  a 
new  mode  of  amalgamating. — Feb.  1852. 


• 


CONTENTS. 


I.— INTRODUCTORY  OBSERVATIONS. 

PAGE 

Voltaic  Electricity  .  .  .  .  .14 

Electrolysis  .  .  .  .  .  .17 

Constant  Voltaic  Battery  .  .  .  .  .19 

Note  on  Voltaic  Batteries  .  .  .  .  .21 


II.— PREPARATION  OF  MOULDS. 


Fusible  Metal        .  .  .  .  .  .26 

To  make  a  Mould  in  Fusible  Metal  .  .  27 

Clichee  Moulds      .  .  .  .  .28 

Wax  Moulds  .  .  .  .  .  .31 

Stearine  Moulds,  &c.  .  .  .  .32 

To  copy  Plaster-Casts       .  .  .  .  .33 

To  render  Non-Metallic  Moulds  conductible  .  .  34 

Plaster  of  Paris  Moulds    .  .  .  .  .38 

Elastic  Moulds      .  .  .  .  .  .39 

Gutta  Percha  Moulds        .  .  .  .  .40 


xii 


CONTENTS. 


III.— VOLTAIC  APPARATUS  TO  BE  USED. 

PAGE 


Amalgamation       .          .  .  .  .  .42 

New  Process  of  Amalgamation  .  .  .  .  .42 

Diaphragms          .          .  .  .  .  .43 

Single-Cell  Apparatus       .  .  .  .  .44 

Single  Cell  without  Acid  or  Mercury  .  .  .46 

Battery  Apparatus           .  .  .  .  .48 

Solutions    .          .          .  .  .  .  .49 

Battery  Apparatus  extended  .  .  .  .53 

Smee's  Battery      .          .  .  .  .  .55 

New  Electrotype  Battery  .  .  .  .  .57 

Electro-Lace         .          .  .  .  .  .58 

Constant  Acid  Battery       .  .  .  .  .59 

Prince  Bagration's  Battery  .  .  .  .60 

The  Earth  a  Battery         .  .  .  .  .60 

Decomposition  Cells          .  •  .  .  .61 

Management  of  the  Moulds  .  .  .  .63 

Management  of  the  Battery  Apparatus  .  .  .65 


IV. — BRONZING. 

Chemical  Bronze    .  .  .  .  .  .69 

Black-Lead  Bronze  .  .  >  .  .71 

Carbonate  of  Iron,  Bronze,  &c.     .  .  .  .72 

Mounting  the  Medals        .  .  .  ...  72 


V.— CONCLUDING  OBSERVATIONS 


73 


ELECTROTYPE  MANIPULATION. 


L— INTRODUCTORY  OBSERVATIONS. 

1.  The  object  of  the  present  treatise  is  not  so  much 
to  dwell  upon  the  philosophical  principles  on  which  the 
art  of  Electrotype  is  based,  as  it  is  to  trace  in  a  familiar 
manner  the  several  processes  in  manipulation,  and  the 
precautions  to  be  observed  in  order  to  escape  failure. 
The  instructions  given  are  the  results  of  a  long  course 
of  experiment ;  and  it  will  be  the  especial  aim  of  the 
writer  to  dwell  minutely  upon  those  little  points  which 
so  materially  influence  the  success  of  the  experiments. 
It  will  be  his  endeavor  to  avoid,  as  much  as  may  be, 
the  use  of  scientific  phraseology )  so  that  the  amateur, 
for  whose  use  this  work  is  written,  may  find  as  few  ob- 
structions as  possible  besetting  his  path.  In  the  course 
of  forming  a  large  collection  of  medals  by  the  electro- 
type process,  and  copying  casts  of  large  size,  the  author 
has,  of  necessity,  been  led  to  adopt  such  modes  as  con- 
venience and  economy  dictated.  These  will  be  described 
in  order,  as  the  reader  is  led  from  the  original  medal  to 
the  perfect  copy,  ready  for  the  cabinet. 
2 


14 


ELECTROTYPE  MANIPULATION. 


2.  Galvano-plastic,  Electrotype,  or  Electro-inetal- 
lurgy,  is,  as  its  several  names  indicate,  intimately  con- 
nected with  Galvanic,  or,  as  it  is  more  fitly  termed, 
Voltaic  Electricity.  In  order,  therefore,  to  convey  cor- 
rect notions  on  the  subject,  it  will  be  requisite,  before 
entering  on  it  further,  to  give  a  brief  outline  of  the 
principles  of  this  science,  and  to  trace  their  application 
to  the  art  in  question. 

3.  Voltaic  Electricity. — Galvanism,  or  Voltaic  Electri- 
city, is  the  name  given  to  that  development  of  electricity 
discovered  in  the  year  1790,  by  Professor  Galvani,  of 
Bologna,  and  subsequently  more  fully  investigated  by 
the  labors  of  Volta,  whose  letter  to  Sir  Joseph  Banks, 
the  then  President  of  the  Boyal  Society,,  announcing 
the  discovery  of  the  apparatus,  named  after  him  the 
Voltaic  pile,  is  dated  March  20,  1800.  It  is  obtained 
by  certain  arrangements  of  metals  and  liquids,  of  which 
the  following  may  be  taken  as  an  illustration.  If  a 
piece  of  zinc  and  another  of  copper  be  attached  one  to 
each  end  of  a  wire,  and  the  two  be  then  placed  in  a 
vessel  containing  water,  acidulated  with  sulphuric  acid, 
it  will  constitute  a  simple  or  single  voltaic  pair  in 
ACTION. 

4.  The  action  is  dependent  on  the  different  chemical 
affinity  of  the  liquid  for  the  respective  metals ;  it  will 
dissolve  the  zinc  rather  than  the  copper:  in  other 
words,  the  water  (which  is  well  known  to  consist  of  the 
two  gases,  oxygen  and  hydrogen,  chemically  combined) 
is  decomposed;  the  hydrogen  makes  its  escape  at  the 
surface  of  the  copper  plate  in  the  form  of  gas;  the  oxy- 


INTRODUCTORY  OBSERVATIONS. 


15 


gen  combines  with  the  zinc,  and  forms  an  oxide  of  zinc  ; 
this  oxide  unites  with,  and  is  dissolved  in  the  sulphuric 
acid,  forming  sulphate  of  zinc.  Actions  analogous  to 
this  occur  in  all  voltaic  combinations.  The  exciting 
liquid  has  a  greater  affinity  for  one  metal  than  for  the 
other.  The  former  is  termed  the  positive  metal )  the 
latter  the  negative. 

5.  For  most  practical  purposes,  zinc  is  used  as  the 
positive  metal — either  pure  zinc,  the  zinc  of  commerce, 
or  amalgamated  zinc  (§  46).  For  the  negative  metal, 
copper  is  generally  used;  but  a  very  convenient  ar- 
rangement has  been  devised  by  Mr.  Alfred  Sniee  (§  65), 
wherein  platinized  silver — that  is,  silver  covered  with 
minute  particles  of  platinum — is  employed.  Another 
battery  has  been  constructed  by  Professor  Grove,  of  a 
very  powerful  nature,  wherein  plates  of  platinum  are 
used.  There  is  also  a  modification  of  this  latter,  con- 
sisting of  zinc  and  charcoal.  Charcoal  or  carbon,  being 
the  only  other  substance  in  nature,  not  metallic,  which 
can  be  so  employed. 

6.  I  have  here  spoken  (§  4)  only  of  the  cliemical 
change  which  takes  place  ;  but  in  connection  with  this, 
and  bearing  a  strict  relation  to  it,  is  another  pheno- 
menon of  the  highest  interest,  namely,  the  disturbance 
of  electric  equilibrium. 

7.  During  the  continuance  of  the  chemical  changes 
already  described  (§  4),  a  transfer  of  electricity  is 
quietly  taking  place  between  the  two  metals.  The  po- 
sitive electricity  (which,  to  avoid  circumlocution,  we 
will  assume  to  be,  as  possibly  it  is,  the  electricity) 


1G  ELECTROTYPE  MANIPULATION. 

passes  from  the  zinc  through  the  liquid  to  the  copper, 
and  then  continues  its  course  along  the  wire  (§  3),  by 
which  the  metals  are  joined,  to  the  zinc  again.  If  the 
wire  is  broken,  the  transfer  of  electricity  is  interrupted, 
and  the  chemical  effects,  so  far  as  electricity  is  con- 
cerned,* cease;  hydrogen  is  no  longer  evolved  from  the 
copper  plate,  and  the  zinc  (if  it  is  pure  or  amalga- 
mated), ceases  to  be  dissolved. 

8.  The  fundamental  principle,  which  cannot  be  too 
strongly  enforced,  is,  that  the  passage  of  the  electricity 
in  the  liquid  is  from  the  zinc  to  the  copper.  If  this 
simple  fact  is  borne  in  mind,  it  will  decide  in  every 
case  the  question  which  confuses  so  many,  namely, 
which  is  the  positive  and  which  is  the  negative  end  of 
a  battery  ?  The  positive  is  the  end  where  the  elec- 
tricity leaves  a  battery )  the  negative  where  it  re-enters 
it.  The  direction  taken  by  the  current  being  ascertained 
by  the  mere  inspection  of  the  situations  of  the  two 
metals  in  a  cell,  the  other  points  follow  as  a  necessary 
consequence. 

9.  If,  for  instance,  the  wire  connecting  the  two 
plates  (§  3),  by  which  we  have  illustrated  a  single  vol- 
taic pair,  were  broken,  and  the  circuit  completed  by  in- 
terposing some  apparatus  between  the  broken  ends,  an 
examination  of  the  arrangement  would  at  once  show 
that,  as  the  electricity  passes  from  the  zinc  to  the  cop- 
per, it  would  leave  the  battery  by  the  wire  attached  to 


*  The  ordinary  chemical  effects  of  the  acid  on  the  zinc 
continue,  unless  prevented  by  other  means  (§  46).  <* 


INTRODUCTORY  OBSERVATIONS. 


17 


the  copper  plate,  and,  having  passed  through  the  inter- 
posed apparatus,  would  return  to  the  battery  by  the 
wire  attached  to  the  zinc  plate;  the  copper,  which  is 
the  negative  metal,  forming  in  this  case  the  positive  end 
of  the  battery ;  and  the  zinc,  the  positive  metal,  forming 
the  negative  end. 

10.  Electrolysis. — The  great  effects  of  voltaic  elec- 
tricity, those  which  have  rendered  it  so  attractive  a 
science,  depend  on  the  various  modes  of  combining  a 
large  or  small  number  of  these  pairs  of  metals,  and  on 
the  nature  of  the  apparatus  interposed  between  the 
wires  connected  with  the  respective  ends  of  the  arrange- 
ment. The  power  which,  from  its  effects,  Dr.  Faraday 
has  termed  the  Electrolytic*  power,  is  that  which  alone 
demands  our  attention,  because  on  the  right  understand- 
ing of  this  depends  the  successful  application  of  the 
art  of  electrotype. 

11.  If  a  series  of  about  ten  of  these  voltaic  pairs  or 
batteries  be  arranged  in  the  order  of  zinc,  liquid,  and 
copper,  and  the  terminating  wires,  which  for  this  purpose 
should  be  of  platinum,  be  placed  in  a  vessel  of  water 
containing  sulphuric  acid,  f  the  water  will  be  electro- 
lyzed  or  decomposed  by  electricity  ;  the  hydrogen  gas 
will  be  released  at  the  wire  connected  with  the  negative 
end  of  the  battery,  and  the  oxygen  at  that  connected 

*  Vide  Exp.  Researches.    Series  7,  \  664. 

f  In  this  and  all  other  similar  instances  the  use  of  sulphuric 
acid  is  to  increase  the  conducting  power  of  the  liquid ;  to 
facilitate  the  passage  of  electricity  through  it.  The  modus 
operandi  cannot  be  entered  into  here. 

2* 


18 


ELECTROTYPE  MANIPULATION. 


with,  the  positive.  If  these  gases  be  collected  separately 
in  tubes  placed  over  the  platinum  wires,  the  quantity 
of  hydrogen  will  in  bulk  be  double  that  of  the  oxygen. 

12.  If  into  this  acid  liquid  some  crystals  of  sulphate 
of  copper  be  thrown,  and  the  current  be  sent  through, 
electrolysis  will  still  take  place,  the  water  will  still  be 
decomposed,  but  only  one  of  the  gases,  the  oxygen,  will 
be  obtained.  The  hydrogen,  as  it  becomes  released 
from  the  water,  will  take  the  place  of  the  copper  in  the 
solution,  and  the  copper  will  be  liberated  and  become 
visible  on  the  negative  (§  8)  wire.  This  experiment 
may  be  continued  till  all  the  copper  is  abstracted  from 
the  solution  •  the  remaining  liquid  will  be  water, 
strongly  acid. 

13.  A  third  modification  of  this  experiment  is  by 
using  for  the  positive  wire  one  of  copper,  instead  of 
platinum.  In  this  instance,  too,  the  water  is  decom- 
posed ;  but  neither  of  the  gases  is  visible.  The  hydro- 
gen, as  before,  occupies  the  place  of  the  copper  in  the 
solution,  releasing  the  copper  as  in  the  last  experiment 
(§  12) ;  the  oxygen,  instead  of  appearing  at  the  positive 
wire,  combines  with  the  copper  of  which  that  wire  is 
composed,  forming  an  oxide  of  copper :  this  oxide 
unites  with  the  sulphuric  acid,  and  forms  a  sulphate  of 
oxide  of  copper.  In  proportion  as  the  solution  is 
weakened  by  the  release  of  copper  at  the  negative  wire, 
it  is  thus  supplied  with  copper  from  the  positive.  If, 
in  these  experiments,  a  measuring  instrument  had  been 
included  in  the  circuit,  it  would  be  found  that  the  first 
of  the  three  presented  the  greatest  resistance,  and  the 


INTRODUCTORY  OBSERVATIONS. 


19 


last  the  least.  For,  in  the  last  case,  the  chemical  forces 
were  made  to  conspire  with  the  electric  current. 

14.  It  will  be  observed,  in  these  illustrations  of  elec- 
trolysis, that  the  metals  are  released  at  the  negative 
plate.  One  part  of  the  science  of  electrotype — a 
science  discovered  in  England  by  Mr.  Jordan  and  Mr. 
Spencer,  and  on  the  continent  by  Professor  Jacobi — 
consists  in  preparing  for  a  negative  plate  models  or 
moulds  (§  20,  &c.)  of  objects  to  be  copied;  and  in  so 
arranging  the  battery  or  apparatus  which  generates 
the  voltaic  current  (§  43,  &c.)  as  to  release  the  metals 
in  a  compact  and  solid  form  upon  these  models. 

15.  On  these  two  points  many  precautions  are  to  be 
observed ;  but  a  faithful  compliance  with  the  directions 
to  be  given  will  enable  the  least  skilled  to  obtain  me- 
tallic copies  of  the  most  beautiful  works  of  art,  by 
merely  exercising  ordinary  care  and  a  little  patience. 

16.  Constant  Voltaic  Battery. — Before  closing  these 
preliminary  observations,  it  will  be  requisite  to  give 
a  brief  description  of  the  Constant  Battery.  The 
voltaic  pair  immersed  in  a  cell  of  acid  water  (§  8)  is 
liable  to  some  objections.  First,  the  bubbles  of  hy- 
drogen released  on  a  common  copper  plate  partially 
adhere,  and  of  necessity  prevent  portions  of  this  plate 
from  being  in  actual  contact  with  the  liquid ;  and 
hence  its  power  is  less  than  it  might  be.  The  dissolved 
zinc,  too,  is  partially  released  and  deposited  on  the 
copper  or  negative  plate,  according  to  the  laws  already 
illustrated  (§  13) ;  hence  arise  counter-currents,  which 
weaken  the  force. 


20  ELECTROTYPE  MANIPULATION. 


17.  The  late  Professor  Daniell,  by  the  invention  of 
his  constant  battery,  has  enabled  us  to  overcome  in  a 
very  great  measure  these  difficulties — to  remove  these 
objections.  The  deposition  of  the  zinc  is  obviated 
by  using  two  liquids,  separated  by  a  porous  partition, 
or,  as  it  is  called,  a  diaphragm,  of  animal  membrane, 
paper  (§  44),  earthenware,  plaster  of  Paris,  wood,*  &c. 
(§  48).  The  liquid  contiguous  to  the  zinc  is,  as  before 
(§  11),  acidulated  water ;  that  near  the  copper  is  a  so- 
lution of  sulphate  of  copper.f  By  this  arrangement,  it 
will  be  seen,  from  what  has  been  already  stated  (§  13), 
that  copper  will  be  released,  in  place  of  hydrogen  on 
the  copper — the  negative  plate. 

18.  The  continuous  action  of  this  battery  is  preserved 
by  amalgamating  (§  46)  the  zinc,  and  supplying  the 
cupreous  solution  with  crystals  of  sulphate  of  copper 
(§  50).  The  former  prevents  the  acid  acting  chemically 
on  the  zinc  (§  7)  and  destroying  it  uselessly :  the  latter 
keeps  up  the  strength  of  the  solution,  which  is  being 
constantly  exhausted  by  the  reduction  of  the  copper. 
Fresh  acid  water  is  occasionally  added. 

This  instrument  is  termed  a  constant  battery,  from 
its  power  of  continuing  a  generally  steady  action  for  a 
lengthened  period  of  time.  It  has  been  constructed  in 
various  ways,  being  modified  according  to  the  taste  of 
individuals,  or  to  the  use  to  which  it  is  to  be  applied. 


*  Lime-tree  or  some  other  porous  wood,  boiled  for  an  hour 
at  least  in  water  containing  a  little  sulphuric  acid. — JacobL 
f  This  is  more  properly  termed  sulphate  of  oxide  of  copper. 


INTRODUCTORY  OBSERVATIONS. 


21 


Fig.  1. 


But  whatever  form  may  be  given  to  it,  it  is  still  the 
constant  battery,  invented  by  Professor  Daniell,  to 
whom  alone  the  credit  is  due  for  devising  so  valuable 
an  arrangement.  The  wood-cut  (Fig.  1)  represents  a 
cell  of  a  Daniell' s  battery.  The  cell,  being  of  copper, 
itself  forms  the  negative  metal.  A  rod  of  amalgamated 
(§  46)  zinc  is  placed,  as  shown  in  the 
figure,  within  a  tube  of  porous  earthenware. 
Attached  to  each  metal  is  a  binding  screw, 
to  form  connections.  A  cell  of  this  de- 
scription is  put  into  action  by  placing  its 
several  parts  as  shown  in  the  figure;  filling 
the  porous  tube  containing  the  zinc  with  a 
mixture  of  one  part  sulphuric  acid  and  ten 
parts  water;  and  filling  the  copper  cell 
with  a  saturated  solution  of  sulphate  of 
copper. — By  saturated  is  meant  a  solution 
containing  as  muck  of  the  salt  of  copper  as  the  water 
will  take  up.  This  is  prepared  most  readily  by  pouring 
boiling  water  on  a  superabundance  of  crystals  of  sul- 
phate, and  stirring  them;  to  this  solution  one-tenth 
acid  should  be  added.  The  perforated  metal  shelf, 
shown  in  the  figure,  is  to  support  a  supply  of  crystals 
to  recruit  the  exhausted  strength  of  the  battery  (§  50). 
The  crystals  are  placed  thus  high  up  in  the  liquid, 
because  the  upper  portions  are  exhausted  first;  the 
specific  gravity  keeps  the  strong  parts  of  the  solution 
below. 

19.  Note  on  Voltaic  Batteries. — While  on  the  sub- 
ject of  voltaic  pairs,  it  will  be  as  well  to  pen  a  few 


22 


ELECTROTYPE  MANIPULATIONS. 


lines  on  the  powers  of  the  battery,  which  are  not  di- 
rectly connected  with  the  art  of  electrotype. — If  a  cell 
of  the  constant  battery  be  charged  as  directed  above, 
and  a  piece  of  fine  platinum  wire  be  stretched  from  the 
screw  attached  to  the  zinc,  to  that  attached  to  the  cop- 
per, it  will  attain  a  red  or  a  white  heat.  This  is  termed 
the  "  heating  power"  of  a  battery.  The  larger  the 
cell,  the  greater,  thickness  of  wire  will  be  heated.  If 
too  thin  a  wire  be  used,  the  passage  of  the  electricity 
will  be  so  much  retarded  as  to  produce  no  visible  indi- 

Fig.  2. 


cations  of  heat.  The  length  of  wire  that  can  be  heated 
depends  on  the  cooling  power  of  the  contiguous  air  ; 
"a  current  that  will  heat  one  inch  of  platinum,  will 


INTRODUCTORY  OBSERVATIONS. 


23 


heat  a  hundred  inches/7*  The  law  which  regulates  the 
comparative  length  of  wires  heated  by  different  combi- 
nations of  the  batteries  appears  to  be  this  :  If  one  such 
cell  as  that  described,  heats  x  inches,  and  another  cell 
y  inches,  the  two  arranged  in  series  will  heat  x-\-y 
inches. f 

If  a  series  of  cells  be  arranged,  as  in  the  preceding 
figure,  by  uniting  the  copper  of  one  to  the  zinc  of  the 
other,  and  points  of  charcoal  be  attached  to  the  termi- 
nating wires,  upon  bringing  these  points  into  contact 
and  then  separating  them,  the  well  known  phenomenon 
of  the  voltaic  flame  is  produced.  The  length  of  this 
flame  depends  on  the  number  of  cells  used ;  the  size 
or  thickness  (if  we  may  use  the  term)  on  the  size 
of  the  cells.  The  flame  from  a  hundred  cells  is 
very  brilliant ;  in  some  experiments  at  which  I  assisted, 
made  with  a  series  of  upwards  of  three  hundred,  it  was 
needful  to  screen  the  eyes  with  a  black  silk  veil.  J  Few 
things  resist  the  intense  heat  of  this  flame ;  the  metals 
are  speedily  dissipated  in  fumes ;  platinum  and  gold  are 
melted  and  vaporized. — The  arrangement  of  cells  in 
series  will  produce  a  shock  on  the  human  frame,  intense 
in  proportion  to  the  number  in  the  series.  Thirty  will 
produce  the  effect;  three  hundred  will  produce  more 
than  a  man  with  ordinary  nerves  could  endure.  The 


#  Faraday's  Researches.    Thirteenth  Series.    $  1631. 
f  Transactions  Electrical  Society,  p.  63.    $  36. 
J  Since  the  above  lines  were  written,  active  exertions  have 
been  made  to  apply  this  light  to  ordinary  purposes. — June,  1849. 


24 


ELECTROTYPE  MANIPULATIONS. 


electrolytic  power  of  the  battery  is  only  manifested  on 
bodies  in  solution,  or  on  bodies  made  liquid  by  heat ; 
and  these  several  bodies  are  acted  upon  with  various 
degrees  of  facility.  Solution  of  iodide  of  potassium  is 
most  easily  decomposed.  A  battery  consisting  of  a 
mere  wire  of  zinc  and  one  of  copper,  will  decompose 
this  solution,  even  by  means  of  platinum  wires.  Water 
is  more  difficult  of  decomposition.  Ten  cells  of  a  DanielPs 
battery  are  a  convenient  number  to  effect  the  decompo- 
sition of  water.  A  series  of  twenty  will  release  very  little 
more  gas  than  one  of  ten;  but  two  series  of  ten  placed 
side  ~hy  side  will  do  twice  the  work  of  one  series.  By  an 
arrangement  of  this  kind  it  is  that  the  maximum  of  de- 
composing power  is  obtained  from  a  given  number  of  cells. 
Chlorides  of  lead  or  silver,  or  chlorate  of  potassa,  &c, 
&c,  do  not  conduct  the  current  in  their  solid  state, 
and  therefore  resist  decomposition ;  but,  when  made 
fluid  by  heat,  they  obey  the  same  general  law  as  do 
solutions.  When  sulphuret  of  antimony  is  fused  by  a 
powerful  voltaic  flame,  the  heat  of  the  same  current 
will  keep  it  fused,  while  the  current  itself  decomposes 
it. — One  or  two  thousand  cells  containing  pairs  of 
plates  (copper  and  zinc)  connected  in  series,  and 
charged  with  water,  produce  effects  closely  analogous 
to  those  obtained  by  the  common  electric  machine. 
This  is  termed  a  water-battery. — There  is  a  beautiful 
regularity  in  the  action  of  batteries,  that  cannot  fail 
to  interest  the  most  casual  observer  :  it  is  a  regularity 
to  which  the  attention  of  the  electrotypist  should  be 
especially  directed.    When  a  number  of  cells  are  con- 


INTRODUCTORY  OBSERVATIONS.  25 

nected  in  series  according  to  the  plan  represented  in  the 
wood-cut,  precisely  the  same  amount  of  action  occurs 
in  each.  If  in  one  an  ounce  of  zinc  is  consumed,  so 
also  is  it  in  every  other ;  and  in  each,  too,  a  weight  of 
copper  is  deposited  on  the  surface  equivalent  to  the 
ounce  of  zinc.  And  if  the  terminating  wires  of  this 
apparatus  be  placed  to  produce  the  decomposition  of  a 
solution,  precisely  the  same  amount  of  the  solution  will 
be  decomposed  as  is  equivalent  to  the  quantity  of  zinc 
consumed  or  copper  released  in  each  cell. — If  water  be 
the  subject  of  experiment,  the  same  arrangement  of 
battery  will  release  more  or  less  gas,  according  to  the 
degree  of  conductibility  given  to  the  water  by  means  of 
sulphuric  acid ;  the  less  conductible  it  is,  the  greater 
resistance  it  offers  to  the  passage  of  the  battery  current, 
the  less  gas  is  released,  and  the  less  zinc  is  consumed : 
as  the  conductibility  increases,  the  rate  of  decompo- 
sition is  higher,  and  the  energy  of  the  action  in  each 
battery  cell  is  greater.  There  is  a  harmony  in  all  this 
consistent  with  what  we  have  hitherto  learned  of  the  laws 
of  nature.  The  knowledge  of  this  law  is  no  small 
addition  to  the  science  of  electricity  :  and  it  must  not  be 
forgotten,  that  the  development  of  this  beautiful  system 
of  things  is  due  to  an  English  philosopher,  Faraday, 
whose  perseverance  in  research  has  been  crowned  with 
unusual  success.  Without  dilating  longer  on  these 
general  features  of  the  science,  I  shall  pursue  the  object 
at  present  in  view,  and  endeavor,  with  as  much  brevity 
as  is  consistent,  to  explain  the  nature  of  the  Electro- 
3 


26 


ELECTROTYPE  MANIPULATION. 


type  art,  with  so  much  of  its  theory  as,  joined  with 
what  has  been  already  said,  may  guide  the  experimenter 
safely  through  each  process. 

II.— PBEPAKATION  OF  MOULDS. 

20.  I  can  very  reasonably  conclude  that  the  amateur 
will  commence  his  experiments  on  the  smaller  works  of 
art ;  and,  as  a  knowledge  of  the  mode  of  manipulation 
to  copy  these  will,  with  a  little  practical  experience, 
easily  pave  the  way  towards  accomplishing  greater 
things,  I  shall  dwell  principally  on  the  art  of  copying 
medals,  medallions,  seals,  &c,  taking  the  reader  with 
me  through  the  entire  process. 

21.  There  are  many  materials  fitted  for  forming 
moulds;  of  these — -fusible  metal,  wax,  stearine,  gutta 
percha,  and  a  composition  whose  base  is  spermaceti, 
are  mostly  used.  The  first  is  applicable  to  all  medals 
of  ordinary  size — the  others  to  plaster  medallions  and 
larger  medals. 

22.  Fusible  Metal. — This  is  an  alloy,  consisting  of 
bismuth,  tin,  and  lead ;  it  melts  at  a  low  temperature 
— a  few  degrees  below  that  of  boiling  water  ;  and  has 
been  used  as  a  philosophical  toy,  in  the  form  of  spoons, 
which  melt  in  hot  tea.  For  the  latter  purpose,  it  gene- 
rally contains  a  small  portion  of  mercury.  Since  the 
discovery  of  electrotype,  it  has  been  prepared  for  that 
process  without  mercury. 


PREPARATION  OF  MOULDS. 


27 


23.  The  proportion  of  the  different  ingredients  in  a 
pound  of  this  alloy  is  : — 

oz. 

Bismuth  .  .       .  .8 

Tin  .....  3 
Lead      .  .       .  .5 

16  =  1  lb. 

These  should  be  melted  together  in  a  clean  iron  ladle, 
taking  care  to  keep  it  on  the  fire  no  longer  than  is 
necessary  to  produce  the  complete  liquefaction  of  the 
several  ingredients.  When  melted,  pour  the  metal  on 
a  stone  or  marble  slab  in  drops.  Then,  after  having 
rubbed  the  ladle  clean  with  coarse  paper,  return  the 
pieces  of  metal,  re-melt  them,  and  pour  them  out  in 
drops  as  before.  A  third  melting  will  insure  the 
ingredients  being  well  mixed.  To  retain  the  metal  in 
a  fit  condition  for  use,  the  ladle  must  be  frequently 
rubbed  clean ;  and  must  always  be  removed  from  the 
fire  as  soon  as  its  contents  are  melted.  The  former 
insures  a  bright  surface  to  the  mould ;  the  latter  pre- 
serves the  alloy  from  waste  by  oxidation. 

24.  To  make  a  Mould  in  Fusible  Metal. — Melt  some 
in  the  iron  ladle,  and  pour  it  on  a  slab ;  then,  from  the 
height  of  two  or  three  inches,  drop  on  it  the  medal  to 
be  copied,  taking  care  that  the  medal  is  cold.  In  a 
few  seconds  the  metal  will  be  solid,  and  may  be  placed 
to  cool;  when  it  is  cold,  either  with  or  without  a  few 
slight  taps,  the  two  will  separate :  and,  if  proper 
care  has  been  taken,  an  exceedingly  sharp  mould  will 


28 


ELECTROTYPE  MANIPULATION. 


be  obtained.  The  novice  must  not,  however,  be  dis- 
heartened if  his  first  attempts  to  obtain  good  moulds 
fail :  for  there  are  so  many  little  accidents  which  may 
happen,  that  the  most  practised  manipulator  may  have 
to  repeat  his  attempts.  A  slight  shake  of  the  hand 
may  drop  the  medal  irregularly;  too  much  sunk,  for 
instance,  on  one  side.  A  film  of  oxide  may  rest  on  a 
portion  of  the  surface  of  the  melted  metal,  and  render 
the  corresponding  portion  of  the  cast  dull.  Dull  look- 
ing moulds  must  always  be  rejected;  for  so  minutely 
correct  is  the  process  of  electrotype,  that  the  dul- 
ness  of  the  mould  will  be  transferred  to  every  copy 
made  from  it.  Even  if  an  original  medal  be  incau- 
tiously handled,  the  slight  trace  of  a  finger-mark  will 
be  transferred  to  the  mould ;  and  thence  to  the  electro- 
type copies. 

25.  The  fusible  metal  will  not  always  pour  into  a 
round  mass,  to  receive  the  medal :  unless  the  slab  is 
perfectly  level,  it  runs  into  a  stream.  This  is  a 
great  inconvenience,  but  may  be  remedied  by  having  a 
shallow  cavity  (saucer  fashion)  made  in  the  marble ; 
or  by  using  any  article  of  earthenware,  which  the 
kitchen  or  the  laboratory  may  furnish,  suited  to  the 
purpose.  I  have  been  in  the  habit  of  using  the  brown 
stoneware  saucers,  in  which  blacking  is  sold ;  and  in 
them  have  produced  some  of  the  best  moulds.  They 
are  to  be  inverted,  and  the  metal  is  to  be  poured  on 
them. 

26.  Clicliee  Moulds. — The  following  is  the  mode 
adopted  on  the  Continent  for  obtaining  the  beautiful 


PREPARATION  OF  MOULDS. 


29 


casts  of  the  French  medals,  which  are  so  much  admired. 
These  casts  are  in  a  fusible  alloy,  containing  antimony, 
as  well  as  the  other  ingredients  (§  23).  The  composi- 
tion is  : — * 

Bismuth       .....       8  parts 
Tin  .       .       .       .       .  4 

Lead  .    »   .       .       .       .  5 

Antimony     .....  1 

The  metals  should  be  repeatedly  melted  and  poured  into 
drops,  until  they  are  well  mixed. 

27.  A  block  of  wood  is  then  turned  into  a  shape 
similar  to  that  of  a  button-die,  into  one  end  of  which  is 
worked  a  cavity,  the  size  of  the  medal  to  be  copied, 
and  not  quite  so  deep  as  its  thickness;  in  this  cavity 
the  medal  is  placed;  should  it  not  fit  tightly,  a  circle 
of  paper  is  pressed  in  with  it;  the  medal,  being  thus 
firmly  mounted,  is  to  be  copied  in  the  following 
manner : — - 

28.  A  sheet  of  smooth  cartridge-paper  is  fixed,  by 
drawing-pins  or  otherwise,  within  side  a  box  having  sides 
about  four  inches  high,  which  slope  inwards  in  order 
to  prevent  the  metal  from  being  scattered  away;  the 
part  to  be  used  is  very  slightly  oiled  with  a  single  drop 
of  oil;  on  this  is  poured  some  of  the  prepared  alloy, 
which  should  be  removed  from  the  fire  as  soon  as  melted 
(§  23).  The  metal  is  then  stirred  together  with  cards 
until  it  assumes  a  pasty  appearance,  and  is  on  the  eve 


*  Vide  Proceed.  Elee.  Soc.  part  ii.  p.  90,  Aug.  17,  1841. 

3* 


30 


ELECTROTYPE  MANIPULATION. 


of  crystallizing;  if,  at  this  stage,  the  surface  should 
appear  defaced  with  dross,  one  of  the  cards  must  be 
passed  over  it  lightly  and  speedily;  should  no  dross 
appear,  this  part  of  the  process  may  be  omitted.  The 
die  containing  the  medal  must  then  be  held  firmly  in 
the  right  hand,  and  be  struck  gently  and  steadily  upon 
the  solidifying  metal.  Should  an  assistant  be  at  hand 
to  aid  in  this,  it  will  be  as  well ;  for  sometimes  during 
the  brief  interim,  while  the  card  is  being  exchanged  for 
the  die,  the  exact  moment  is  lost,  and  the  mould  is  im- 
perfect. When  one  stirs  the  metal,  and  the  other  is 
prepared  with  the  die,  the  operation  can  be  timed  to  a 
nicety.  When  an  assistant  is  not  at  hand,  the  die 
should  be  placed  within  reach  of  the  right  hand,  with 
the  medal  downwards.  A  little  ingenuity  "will  readily 
suggest  the  construction  of  a  press,  by  which  this  part 
of  the  process  could  be  accomplished.  Large  medals 
are  moulded  without  the  die,  by  dropping  them  in  a 
sidelong  direction  upon  the  solidifying  metal. 

29.  The  beauty  and  perfection  of  moulds  thus  ob- 
tained will  amply  repay  the  trouble  of  producing  them 
— though  I  am  not  quite  justified  in  using  the  word 
"trouble" — for  by  this  mode,  with  ordinary  care,  two 
out  of  every  three  casts  are  perfect;  besides,  therefore, 
the  economy  of  time,  the  saving  in  the  reduced  oxi- 
dization of  metal  is  thus  of  no  inconsiderable  importance. 

30.  This  method  of  producing  moulds  is  not  confined 
to  obtaining  them  from  medals,  which  melt  at  a  high 
temperature;  they  may  be  obtained  from  the  common 
soft,  white  metal,  with  little  danger  of  damaging  the 


PREPARATION  OF  MOULDS. 


31 


original.  They  may  also  be  obtained  from  the  metallic 
casts,  which  are  extant,  of  the  French  medals  of  Andrieu, 
&c.  Moreover,  if  the  fusible  mould  itself  be  cut  round 
and  fitted  into  the  block  in  place  of  the  medal,  it  may 
be  employed  as  a  die  j  and  casts,  perfect  casts,  equal  in 
respect  to  fidelity,  and  similar  to  the  original  medal, 
may  be  obtained. 

31.  Having  obtained  a  mould,  varnish  the  back  and 
edge — and  also  a  portion  of  the  front,  when  the  surface 
of  the  mould  around  the  impression  is  larger  than 
necessary.  The  best  varnish  is  good  sealingwax,  dis- 
solved in  spirit  of  wine;  but  for  immersion  in  the 
cyanide  solutions  to  be  described  hereafter  (§  95),  wax, 
or,  which  is  better,  pitch  must  be  used.  It  will  now  be 
ready  for  use,  and  is  to  be  attached  to  a  copper  wire. 
The  end  of  this  wire  must  be  quite  clean;  the  wire  is 
placed  across  the  flame  of  the  candle,  with  the  clean  end 
beyond  the  flame;  it  is  to  be  touched  with  a  piece  of 
rosin,  and  pressed  on  the  edge  of  the  mould.  The 
mould  will  instantly  melt  to  receive  it,  and  in  a  few 
seconds  it  will  be  cold  and  firmly  fixed.  The  moulds 
should  be  wrapped  in  paper,  if  they  are  not  intended  for 
immediate  use. 

32.  Wax  Moulds. — The  manipulation  with  this  ma- 
terial is  very  simple.  The  wax  employed  is  the  common 
white  wax,  or  the  ends  of  wax  candles.  It  is  to  be 
melted  in  an  earthen  pipkin  or  a  small  jug,  and  kept 
by  the  fireside  a  few  minutes  after  it  is  well  melted. 
The  medal  to  be  copied  should  be  made  warm — the 
warmer  the  better  (the  object  being  to  prevent  the 


32 


ELECTROTYPE  MANIPULATION. 


sudden  chill  of  the  wax  when  poured  on).  It  is  to 
be  surrounded  with  a  rim,  composed  of  a  ribbon  of 
pasteboard.  The  end  of  this  may  conveniently  be 
secured  by  a  small  cleft  stick.  The  surface  of  the 
medal  should  be  very  slightly  covered  with  olive  oil. 
The  hot  wax  is  then  poured  on.  It  may  require  five  or 
six  hours  to  become  sufficiently  cold  for  removal ;  and 
great  care  must  be  taken  to  allow  the  cooling  process 
to  be  gradual ;  for,  without  this  precaution,  the  moulds, 
especially  when  of  large  objects,  are  apt  to  split.  There 
will  be  at  times  a  difficulty  in  removing  wax  moulds 
from  medals  with  elaborate  work.  This  may  be  ob- 
viated by  a  little  care  :  the  medal  should  be  very 
slightly  warmed  by  the  heat  of  a  candle,  so  as  to  cause 
a  trifling  expansion  of  the  metal ;  and  the  wax  is  then 
to  be  drawn  cautiously,  and  at  right  angles,  from  the 
surface  of  the  medal.  This  applies  to  other  composi- 
tion moulds. 

33.  Stearine  Moulds,  &c. — From  a  few  practical  in- 
conveniences attendant  on  the  use  of  wax,  I  have  at 
times  preferred  stearine,  and  consider  it  on  the  whole 
very  useful,  especially  in  copying  works  in  metal  j  but 
recent  experience  has  taught  me  that  a  still  better  ma- 
terial, is  a  composition  consisting  of  8  oz.  of  spermaceti 
to  If  oz.  each  of  wax  and  mutton  suet.  The  Rev.  F. 
Lockey  recommends  a  mixture  of  wax,  stearine,  and 
black-lead.  On  this  hint,  I  have  added  black-lead  to 
some  of  my  compositions,  and  with  advantage.  Since 
writing  this  paragraph,  I  have  examined  some  moulds 
made  with  wax  and  a  little  of  what  is  termed  Flake- 


PREPARATION  OF  MOULDS. 


33 


ivliite,  and  never  saw  any  to  equal  them — nay,  not  even 
the  metal  moulds. 

34.  That  such  compositions  will  produce  minutely 
correct  copies  of  plaster  casts  renders  them  invaluable 
to  the  electrotypist,  who  employs  his  scientific  resources 
towards  the  formation  of  a  collection  of  worlds  of  art. 
For  he  is  thus  enabled  to  transfer  impressions  from  the 
frail  and  perishable  plaster  to  the  durable  copper  ;  and  to 
transfer  them  with  all  their  beauty  and  all  their  perfec- 
tion. They  who  have  obtained  but  a  casual  insight  into 
the  treasures  transferred  to  this  delicate,  but  brittle  mate- 
rial, have  seen  enough  to  assure  them  that  there  is  an 
ample  store  to  suit  every  taste  and  every  temper.  For 
a  few  pence,  specimens  of  first-rate  execution  may  be 
obtained  from  any  of  the  plaster-shops  in  London. 

35.  To  copy  Plaster- Casts. — Pour  some  hotting  water 
into  a  plate ;  stand  the  cast,  face  upwards,  in  this 
water  :  the  water  must  not  be  deep  enough  to  reach  the 
face  of  the  cast.  In  a  few  minutes,  the  cast  will  be 
filled  with  water.*  Then,  without  loss  of  time,  wrap 
round  it  a  ribbon  of  pasteboard  as  before  (§  32),  and 
immediately  pour  in  the  melted  composition.  After  it 
becomes  solid,  let  it  remain  for  two  or  three  hours,  and 
the  mould  may  generally  be  lifted  off  from  the  plaster, 
without  further  trouble. 

36.  This,  however,  is  not  always  the  case,  for  if  the 


*  The  small  delicate  casts,  which  are  slightly  tinted,  are 
best  copied  by  first  moistening  their  surfaces  with  olive  oil,  and 
then  pouring  on  the  wax. 


34 


ELECTROTYPE  MANIPULATION. 


water  with  which  the  plaster  is  soaked  be  too  cool,  or 
if  the  cast  be  not  perfectly  saturated,  the  wax  will  ad- 
here ;  and,  even  with  every  care,  this  will  at  times  be 
found  to  occur,  on  account  of  imperfections  in  the 
structure  of  the  cast.  Unless  the  latter  has  been  cast 
from  good  plaster,  very  well  mixed  and  stirred,  it  will 
be  of  a  rotten  texture,  and  will  readily  break  off  in  frag- 
ments after  it  has  once  been  wetted ;  and  these  frag- 
ments will  adhere  to  the  mould.  Having  thus  destroyed 
the  cast,  it  is  an  object  of  some  importance  to  preserve 
the  mould  by  removing  the  fragments  without  affecting 
the  wax  surface.  This  is  readily  done  by  gently  touch- 
ing each  spot  of  plaster  with  a  wire  dipped  in  sulphuric 
acid  ;  and  then  leaving  the  cast  exposed  to  the  air  for 
ten  or  twelve  hours.  The  acid  will  gradually  absorb 
moisture  from  the  atmosphere,  and  their  mutual  action 
will  so  disintegrate  the  plaster,  that  it  may  be  entirely 
washed  away  with  a  earner s-hair  brush  and  cold  water. 

37.  To  render  Non- Metallic  Moulds,  Conductihle. — 
But  wax,  and  such  like  bodies,  are  non-conductors; 
and,  as  such,  will  not  be  of  any  service  to  convey 
the  voltaic  current.  In  order  to  render  their  surface 
conductible,  many  plans  have  been  devised.  There  is 
one  which  combines  the  three  advantages'  of  simpli- 
city, certainty,  and  economy.  It  is,  to  cover  the  sur- 
face with  black-lead ;  the  application  of  this  substance 
was  recommended  by  Mr.  Murray  ;  it  was  also  employed 
by  Prof.  Jacobi,  and  its  management  is  described  in  his 

"  GrALVANO-PLASTIC." 

38.  This  article  is  known  in  commerce  under  the 


PREPARATION  OF  MOULDS. 


35 


several  names  of  plumbago,  graphite,  and  black-lead. 
The  latter  might  naturally  enough  induce  those  unac- 
quainted with  the  subject  to  conclude  that  lead  held 
a  prominent  place  in  its  composition.  This,  however, 
is  not  the  case ;  it  contains  no  lead  at  all ;  it  consists 
of  carbon  and  iron  the  principal  portion  being  carbon. 
Plumbago  is  largely  used  in  the  arts ;  the  finer  sorts 
for  drawing-pencils,  the  inferior  in  domestic  economy, 
for  polishing  iron-work.  It  does  not  seem  that  the 
difference  of  quality  in  this  substance  depends  entirely 
upon  the  quantity  of  carbon  it  contains.  The  common 
qualities,  such  as  are  used  for  polishing  stoves,  are 
very  good  conductors ;  but,  unfortunately,  the  common 
kinds  are  often  largely  adulterated.  The  philosophical 
instrument-makers,  who  sell  the  apparatus  for  Electro- 
type experiments,  generally  keep  plumbago  in  a  fit  con- 
dition for  applying  wax  to  moulds. 

39.  It  may  be  applied  dry.  Having  breathed 
slightly  on  the  mould,  dip  a  soft  brush  into  the  plum- 
bago, and  rub  it  briskly  over  the  surface :  continue 
this,  breathing  on  it  occasionally,  till  the  whole  presents 
the  well-known  black-lead  polish.  Be  very  careful  to 
rub  the  brush  into  every  spot.  The  best  kind  of  brush 
is  a  strong  and  fine  camers-hair  pencil.  With  care, 
this  operation  will  not  affect  the  sharpness  of  the 
mould  in  the  slightest  perceptible  degree.  When  the 
mould  seems  to  be  covered,  if,  upon  breathing  on  it, 
any  parts  appear  whitish,  repeat  the  operation. — In 


Its  chemical  name  is  carburet  of  iron. 


36 


ELECTROTYPE  MANIPULATION. 


some  cases  the  black-lead  may  be  applied  wet,  and  after- 
wards polished. — Messrs.  Elkingtons  used  the  following 
mixture,  instead  of  mere  plumbago :  Zinc  is  melted 
in  an  iron  ladle  until  near  the  point  of  burning,  when 
a  few  pieces  of  iron  are  dropped  into  it.  When  cold, 
the  mixture  is  very  friable.  They  reduce  it  to  a  fine 
powder,  and  mix  it  with  plumbago,  which  they  apply 
as  before. — A  clean  wire  slightly  warmed,  and  pressed 
against  the  back  of  the  mould,  will  become  firmly 
imbedded  in  it.  Then  rub  the  wire  and  the  wax  about 
it  with  the  plumbago  brush,  in  order  to  complete  the 
connection  between  the  two.  It  is  advisable  to  re- 
move any  plumbago  which  may  have  been  spread  on 
the  edges  of  the  mould,  by  scraping  them  with  a  knife. 
The  mould  is  then  ready  for  use,  if  small ;  but  if  large, 
the  u  guiding-wires,"  recommended  by  Mr.  Phillips,  of 
St.  Austell,  may  be  occasionally  added  with  advantage. 
One  or  more  thin  wires  are  twisted  round  the  main 
wire,  and  their  ends  are  allowed  to  rest  against  different 
parts  of  the  mould,  especially  in  the  recesses  of  deep 
relief ;  and  thus  the  copper  may  be  led  to  deposit  over 
all  parts  of  the  surface  in  a  short  time.  When  this  is 
effected,  the  guiding-wires  are  carefully  removed. — 
Sealingwax  impressions  are  coated  with  plumbago. 
To  cause  it  to  adhere,  moisten  the  seal  slightly  with 
spirit  of  wine,  or  expose  it  to  the  vapor  of  ether.  For 
delicate  objects,  as  flowers,  insects,  &c,  which  cannot 
withstand  the  action  of  brushing,  other  modes  must  be 
adopted.  One  method  is  to  dip  the  article  in  a  weak 
solution  of  nitrate  of  silver,  and  while  moist  to  expose 


PREPARATION  OF  MOULDS. 


37 


it  to  the  vapor  of  phosphorus,  under  a  tumbler  or  bell- 
glass.  ,  The  vapor  is  procured  by  placing  a  watch-glass, 
containing  phosphorus  dissolved  in  alcohol,  in  a  saucer 
of  hot  sand.  By  this  operation,  the  metal  silver  is  re- 
duced from  its  nitrate;  and  thus  the  surface  of  the 
article  is  made  conductible.  This  process  has,  in  some 
cases,  been  adopted  conjointly  with  the  plumbago;  on 
large  objects,  the  black-lead  surface  has  been  painted, 
first  with  nitrate  of  silver  in  solution,  and  then  with  the 
solution  of  phosphorus.  The  silver  is  sometimes  re- 
duced by  the  action  of  light;  the  same  object  has  been 
also  accomplished  by  allowing  a  jet  of  sulphurous  acid 
gas  to  impinge  on  the  surface  moist  with  the  nitrate. 
The  best  preparation  of  phosphorus,  however,  is  its  so- 
lution in  bisulphuret  of  carbon.  This  highly  inflam- 
mable and  very  volatile  compound  greedily  dissolves 
phosphorus;  but  about  ^tih  part  of  phosphorus  will  be 
found  sufficient.  The  object  is  merely  dipped  in  this; 
and,  after  a  few  seconds,  is  immersed  for  a  short  time  in 
a  weak  solution  of  nitrate  of  silver,  and  then  allowed  to 
dry  in  the  light.  The  greatest  care  must  be  exercised 
in  these  operations;  for  the  articles  themselves  will 
often  inflame  spontaneously,  if  allowed  to  remain,  after 
having  been  in  the  phosphorus  solution; — it  must  not 
be  dropped  about  ;  for,  although  apparently  innocent  at 
the  moment,  it  may  afterwards  ignite,  and  cause  very 
serious  accidents.  It  must  not  be  allowed  to  insinuate 
itself  beneath  the  nails  of  the  hand.  A  preparation  of 
wax,  containing  a  little  of  this  solution,  is  sometimes 
4  * 


38 


ELECTROTYPE  MANIPULATION. 


used;  it  is  melted,  and  the  objects,  when  dipped  in,  need 
no  further  preparation.* 

40.  Plaster  of  Paris  Moulds. — Another  mode  of 
making  moulds  is  with  fine  plaster.  They  are  to  be 
saturated  with  wax  or  tallow,  by  standing  them  in  a 
shallow  vessel  containing  these  ,  substances  in  a  melted 
state,  or  they  may  have  their  surfaces  covered  with  fine 
varnish  if  the  work  will  permit  it;  or  they  may  be 
heated  with  hot  boiled  oil,  containing  a  little  beeswax; 
and  when  cold  they  are  to  be  coated  with  plumbago 
(§  34).  The  best  fine  plaster  should  always  be  used;  it 
should  be  fresh;  if  kept  any  time,  it  must  be  preserved 
from  the  air  in  jars  or  otherwise.  In  mixing,  water  is 
first  poured  into  a  lipped  basin ;  the  plaster  is  gradually 
dropped  in,  and  the  supernatant  water  poured  away ;  the 
water  which  remains  with  the  plaster  is  the  proper  pro- 
portion to  be  stirred  with  it :  when  well  mixed,  let  a 
small  quantity  be  brushed  into  all  the  work  of  the  medal 
with  a  carneF s-hair  pencil;  this  removes  air-bubbles: 


*  The  following  preparation  is  also  used :  A  pound  of  wax 
or  tallow  is  melted;  to  this  is  then  added  a  solution  consisting 
of  2  oz.  of  India  rubber  and  1  lb.  of  asphalte  dissolved  in  a  pint 
of  spirits  of  turpentine.  To  this  is  added  a  pound  of  a  solu- 
tion of  phosphorus  in  bisulphuret  of  carbon,  in  the  proportion 
of  1  part  of  the  former  to  15  of  the  latter.  The  articles  are 
attached  to  a  wire,  and  dipped  into  this  mixture ;  they  are  then 
dipped  in  a  weak  solution  of  nitrate  of  silver,  and  when  the 
black  appearance  of  the  silver  is  manifested,  they  are  removed 
and  washed  in  water;  they  are  afterwards  dipped  in  a  weak 
solution  of  chloride  of  gold,  and  then  washed.  They  are  now 
coated  with  gold,  and  are  ready  for  the  electrotype  process. 


PREPARATION  OF  MOULD. 


39 


then  pour  on  the  plaster  to  the  thickness  required.  If 
the  objects  to  be  copied  be  lightly  oiled  first,  little  diffi- 
culty will  be  experienced  in  removing  the  plaster-mould 
when  "set"  Fusible  moulds  will,  with  proper  care, 
produce  successively  as  many  electrotype  copies  as  the 
operator  pleases.  Wax  or  composition  moulds  are  most 
commonly  damaged  more  or  less,  in  removing  the  de- 
posit. 

41.  When  the  object  is  undercut,  the  plaster-mould 
may  be  made  in  pieces ;  and  when  put  together  in  a 
mother-piece,  the  joinings  must  be  modelled  up.  I  have 
adopted  this  plan  in  some  electrotypes  of  Thorwalsden's 
" Triumph  of  Alexander;"  in  others,  I  have  made  the 
mould  on  the  plaster-cast,  and  have  then  broken  the  lat- 
ter carefully  away,  so  as  to  leave  me  a  mould  in  a  single 
piece.  In  either  case,  the  mould  requires  to  be  broken 
away  from  the  Electrotype. 

42.  Elastic  Moulds. — Three  parts  of  treacle  are  added 
to  twelve  parts  of  glue  that  has  been  carefully  melted, 
and  the  whole  is  well  incorporated.  Metal  and  other 
objects,  which  would  not  "deliver"  on  ordinary  moulds, 
on  account  of  their  high  relief,  may  be  readily  moulded 
by  this  preparation,  which  will  stretch  during  the  re- 
moval of  the  mould,  and  will  readily  return  to  its  origi- 
nal form. 

Another  Plan.  To  a  pound  of  gelatine  or  of  the 
best  fish  glue,  add  three-quarters  of  a  pint  of  water  and 
half  an  ounce  of  beeswax,  and  dissolve  it  over  the  fire 
in  the  way  of  ordinary  glue  :  use  it  when  at  about  the 
consistency  of  syrup.    The  plaster-cast  must  be  oiled 


40 


ELECTROTYPE  MANIPULATION. 


before  the  mould  is  taken  from  it.  This  is  Mr.  Mitch- 
ell's plan,  and  may  be  at  times  useful. 

Gutta  Percha  Moulds. — This  material  will  be  found 
very  valuable.  In  making  moulds  from  metal  originals, 
a  piece  is  to  be  cut  from  a  sheet  of  gutta  percha  about 
the  size  required ;  and,  after  being  softened  in  water  at 
the  temperature  of  150°  or  160°,  is  to  be  pressed  by 
screw-pressure  or  otherwise  into  the  medal.  Plaster 
originals  may  be  copied  most  accurately,  without  un- 
dergoing any  previous  preparation,  by  the  employment 
of  gutta  percha  macerated  with  a  little  coal  naphtha. 
This  preparation  is  made  very  plastic  by  warm  water, 
and  does  not  require  much  pressure  to  produce  most 
faithful  copies,  and  without  damaging  the  cast.  It  is 
more  convenient  to  purchase  it  prepared  than  to  make 
it.    It  may  be  obtained  of  the  publishers  of  this  book. 

Coating  Glass. — It  is  often  desirable  to  coat  glass 
vessels  with  copper  for  chemical  purposes.  Expose  the 
glass  to  fumes  of  hydrofluoric  acid,  to  roughen  it,  when 
the  vessel  is  of  such  a  shape  that  the  copper  might 
easily  leave  the  glass ;  in  other  cases,  as  in  flasks,  this 
part  of  the  operation  may  be  omitted.  Then  varnish 
and  black-lead  the  vessel.  Use  copal  varnish,  or  two 
parts  of  asphalte  and  one  of  mastic  in  oil  of  turpentine, 
or  gutta  percha  solution. 


VOLTAIC  APPARATUS  TO  BE  USED. 


41 


III.— VOLTAIC  APPARATUS  TO  BE  USED. 

43.  The  moulds  thus  prepared  are  fitted  to  fill  the 
place  of  the  negative  or  copper  plate,  in  the  generating* 
cell  of  a  simple  constant  voltaic  pair  (§  17);  or  of  the 
negative  plate  in  a  decompositionf  cell.  In  either  case 
they  occupy  the  place  where  hydrogen  is  evolved,  if  the 
liquid  is  acid  water  (§§  4,  11)  j  and  where  copper  is 
reduced,  if  this  acid  water  contains  sulphate  of  copper 
(§§  12,  13,  18). 

44.  For  the  simplest  mode  of  obtaining  an  Electro- 
type medal,  the  reader  is  referred  to  the  description 
given  (§  3),  of  a  single  voltaic  pair.  Instead  of  using 
the  copper-plate  as  there  described,  attach  (§  31)  to  the 
end  of  the  wire  one  of  the  fusible  moulds  (§  24).  Bend 
the  wire  into  the  shape  of  the  letter  f|  >  so  that  the 
mould  shall  face  the  zinc  :  wrap  the  zinc  in  a  piece  of 
brown  paper;  pour  within  the  paper  some  salt  and 
water,  or  some  water  very  slightly  acidulated  with 
sulphuric  acid;  and  immerse  the  whole  into  a  vessel 
containing  a  saturated  (§  18)  solution  of  sulphate  of 
copper,  having  a  little  acid  in  it. 

45.  This  apparatus  will  represent  a  single  cell  of  a 
constant  battery  (§  17) ;  not  constructed  on  the  best 


*  This  term  is  applied  to  that  cell  containing  the  single  vol- 
taic pair  of  zinc  and  copper,  or  other  metal  (f  3). 

j-  This  term  is  applied  to  the  second  cell,  into  which  the 
terminating  wires  (g§  11,  12,  13)  are  brought. 

4* 


42 


ELECTROTYPE  MANIPULATION. 


principles,  it  is  true,  but  sufficiently  so  for  an  introduc- 
tory experiment.  The  copper  of  the  solution  will  be 
released  on  the  fusible  mould  (§  17) ;  after  a  few  min- 
utes' immersion,  the  mould  will  be  covered  with  a  very 
brilliant  coating  of  pure  metallic  copper ;  after  thirty 
hours,  or  less,  with  proper  arrangements  (§  58),  this 
coating  will  be  thick  enough  to  remove. 

46.  Amalgamation. — To  complete,  however,  the  cha- 
racter of  this  constant  voltaic  pair,  the  zinc  must  be 
amalgamated  )  for  besides  the  electric  action  into  which 
common  zinc  may  enter,  the  acid  acts  on  it  chemically. 
This  partly  arises  from  the  quantity  of  foreign  matter 
contained  in  the  zinc  of  commerce  :  this  matter,  which 
is  mostly  metallic,  forms,  with  the  particles  of  zinc, 
very  many  small  voltaic  pairs,  all  acting  independently 
of  the  negative  plate  (§§  3,  17),  and  at  the  expense  of 
the  zinc  and  acid.  Pure  zinc,  which  may  be  obtained 
where  electrotype  apparatus  is  sold,  is  not  to  this  extent 
destroyed. 

47.  The  process  of  amalgamation  is  this :  Place 
some  mercury  in  a  saucer  or  plate )  pour  on  it  some 
water  and  sulphuric  acid ;  brush  the  liquid  and  mer- 
cury over  the  surface  of  the  zinc,  till  the  whole  is 
covered  with  a  bright  coat  of  mercury.* 


*  New  Process  of  Amalgamation. — At  the  meeting  of  the 
British  Association  in  1849,  Mr.  Walenn  gave  the  following 
process  of  Amalgamation:  "  After  the  plates  are  cleaned  with 
emery,  immersion  in  dilute  sulphuric-acid,  and  then  in  water, 
they  are  dipped  into  a  mixture  of  about  equal  parts  by  measure 
of  saturated  solutions  of  chloride  of  mercury  (corrosive  subli- 


VOLTAIC  APPARATUS  TO  BE  USED. 


43 


48.  Diaphragms. — But  the  paper  diaphragm  above 
mentioned  is  very  inconvenient  in  experiments  of  any 
duration;  it  seldom,  perhaps  never,  prevents  the  partial 
mixing  of  the  liquids ;  and  its  use  is  always  attended 
with  a  great  waste  of  the  sulphate  of  copper.  The 
same  may  be  said,  though  in  a  less  degree,  of  animal 
membrane.  Either  will  do  very  well  for  solitary  ex- 
periments; but  something  more  substantial  and  more 
durable  is  requisite.  For  this  purpose  porous  tubes 
have  been  constructed  of  the  material  used  for  butter- 
coolers  :  others  have  been  made  of  pipe-clay. 

49.  Very  good  diaphragms  are  easily  made  from 
plaster  of  Paris ;  and  for  this  purpose  the  coarse 
plaster  used  by  builders  is  best,  care  being  taken  to 
have  it  as  new  and  fresh  as  possible  :  it  is  mixed  with 
water  in  the  usual  way  (§  40),  and  is  poured  into  a 
mould  of  the  following  construction  :  A  core  is  turned 
out  of  hard  wood,  nearly  cylindrical,  but  a  little  smaller 


mate)  and  acetate  of  lead ;  they  are  then  rubbed  with  a  cloth, 
and  are  ready  for  use.  The  superiority  of  this  method  of 
preparing  the  plates  consists  in  the  fact  that  local  action  is 
entirely  prevented,  and  they  only  require  one  preparation  until 
they  are  quite  dissolved ;  they  are  not  so  liable  to  break  as 
common  amalgamated  plates  are,  and  are  therefore  able  to  be 
used  as  long  as  any  metal  remains.  They  are  also  more  highly 
positive  than  common  amalgamated  zinc  plates." 

Should  this  process  be  found  in  practice  to  maintain  the  cha- 
racter here  assigned  to  it,  it  will  be  of  unquestionable  value. 
I  am  testing  it  on  an  extensive  scale,  with  batteries  that  will 
be  required  to  remain  efficient  for  many  months  together. 


44 


ELECTROTYPE  MANIPULATION. 


at  one  end,  in  order  that  it  may  draw  out  of  the 
diaphragm  when  made )  the  thicker  end  has  a  shoulder 
rising  a  quarter  of  an  inch  or  more  beyond  the  surface 
of  the  core,  according  to  the  thickness  required  to  be 
given.  This,  as  well  as  the  length  and  diameter  of  the 
core,  will  depend  on  the  kind  of  diaphragm  required. 
A  thin  sheet  of  tin  or  copper  is  now  tied  round  the 
shoulder ;  and  plaster  being  poured  between  the  core 
and  the  envelop,  a  diaphragm  is  readily  made.  These 
diaphragms  are  very  durable;  and  will  be  found  a  great 
acquisition  to  those  who,  from  local  circumstances,  may 
not  be  able  to  obtain  other  kinds  of  porous  ware. 

50.  If,  in  the  introductory  experiment  already 
described,  the  amalgamated  zinc  and  these  diaphragms 
be  employed,  a  constant  battery  is  obtained,  with  all 
its  parts  complete.  And  if,  in  addition,  a  bag  of 
crystals  of  sulphate  of  copper  be  hung  in  the  blue  solu- 
tion, in  order  to  recruit  its  strength,  and  the  acid 
water  around  the  zinc  be  occasionally  renewed,  the 
action  may  be  continued  for  days  or  even  weeks.  And 
by  removing  the  mould  as  soon  as  a  sufficient  thick- 
ness of  copper  is  obtained,  and  supplying  its  place  by 
another,  three  or  four  medals  may  be  copied  in  a  week. 

51.  Single-cell  Apparatus. — The  annexed  wood-cut 
(Fig.  3)  represents  the  single-cell  apparatus  in  its  com- 
plete form,  z  is  a  rod  of  amalgamated  zinc,  m  the  mould, 
w  the  wire  joining  them,  c  the  copper  solution,  p  a  tube 
of  porous  earthenware,  containing  a  solution  of  acid  and 
water.  To  put  this  in  action,  pour  in  the  copper  solu- 
tion, fill  the  tube  with  the  acid  water,  and  place  it  as 


VOLTAIC  APPARATUS  TO  BE  USED.  45 


shown  in  the  figure.  Last  (§  75)  of  all  put  in  the  bent 
wire,  having  the  zinc  at  one  end  and  the  mould  at  the 
other.  Another  form  of  this  apparatus  is  here  given 
(Fig.  4).    The  zinc  is  connected  by  a  wire  and  binding 


Fig.  3.  Fig.  4. 


screws  with  a  metal  rim )  and  on  the  latter  can  be  hung 
several  moulds,  as  in  the  drawing.  Things  are  much 
more  likely  to  go  on  well  when  several  moulds,  as  thus, 
are  operated  on,  than  when  only  one  is  introduced. 
The  reason  will  be  manifest  hereafter. 

52.  The  following  precautions  must  be  observed  in 
using  this  apparatus  :  The  copper  solution  must  be  kept 
saturated,  or  nearly  so ;  this  is  effected  by  keeping  the 
shelf  well  furnished  with  crystals.  The  mould  must 
not  be  too  small  in  proportion  to  the  size  of  the  zinc. 
The  concentrated  part  of  the  solution  must  not  be 
allowed  to  remain  at  the  bottom.  In  the  latter  case, 
the  copy  will  be  irregular  in  thickness — in  the  former, 


46 


ELECTROTYPE  MANIPULATION. 


the  metal  may  be  a  compact  brittle  mass;  or  may  be 
deposited  in  a  dull  red,  a  violet,  or  a  black  powder. 
The  nature  of  these  several  depositions  will  be  elsewhere 
alluded  to  (§  62,  &c);  so  will  also  the  relative  pro- 
portions of  the  zinc,  &c.  (§  78). 

53.  Single  Cell  without  Acid  or  Mercury. — The  tyro 
must  not  imagine  from  the  above  descriptions  that  acid 
and  mercury  are  the  sine  qua  non  of  success;  because 
either  of  the  above  apparatuses  would  be  effective,  though 
in  a  feebler  degree,  by  charging  the  porous  tube  with  a 
solution  of  sal-ammoniac,  or  even  with  one  of  common 


salt,  and  using  zinc  in  its  ordinary  state,  and  employing 
a  neutral  solution  of  sulphate  of  copper.  Sal-ammoniac, 
or  hydrochlorate  of  ammonia,  consists  of  ammonia  and 


Fig.  5. 


VOLTAIC  APPARATUS  TO  BE  USED. 


47 


muriatic  acid.  Its  electro-chemical  analysis  is  too  com- 
plex to  need  a  place  here.  Table  salt  or  chloride  of 
sodium,  consists  of  the  gas,  chlorine,  and  the  metal, 
sodium :  its  action  is,  that  the  chlorine  combines  with 
the  zinc,  and  forms  the  very  soluble  chloride  of  zinc ; 
and  the  sodium  combines  with  the  oxygen,  that  would 
be  nascent  at  the  diaphragm,  and  forms  soda.  This  ar- 
rangement is  not  so  powerful  as  the  other,  because  the 
sum  of  the  favorable,  minus  the  unfavorable,  affinities  is 
less  in  the  one  case  than  in  the  other. 

54.  A  single-cell  apparatus  may  consist  of  a  wooden 
box,  as  shown  above  (§  53),  well  varnished  in  the  in- 
terior, and  divided  into  two  unequal  cells  by  a  partition 
of  porous  wood.  The  wood  is  prepared  as  described 
above  (§  17).  The  larger  cell  is  filled  with  a  saturated 
solution  of  sulphate  of  copper,  the  smaller  with  a  half- 
saturated  solution  of  muriate  of  ammonia,  or  one  of 
common  salt.  In  the  former  is  a  shelf  for  containing  a 
supply  of  crystals. 

55.  I  do  not  recommend  the  use  of  the  single-cell 
arrangement,  except  for  small  objects ;  I  do  not  adopt  it 
on  the  large  scale.  Seals  are  electrotyped  by  the  sim- 
plest form  of  the  single  cell :  a  warm  wire  is  pressed 
into  the  edge  of  the  seal,  which  is  then  covered  with 
plumbago;  the  other  end  of  the  wire  is  twisted  to  a 
little  piece  of  zinc,  or  even  an  iron  nail,  and  the  wire  is 
bent  p|  fashion  :  a  little  diaphragm  of  card,  sewed  up, 
having  the  joinings  secured  with  wax,  is  filled  with 
water  containing  a  pinch  of  salt,  or  a  few  drops  of  acid; 
this  is  placed  in  a  tumbler  of  sulphate  of  copper ;  and 


48 


ELECTROTYPE  MANIPULATION. 


the  seal  is  immersed  in  the  copper  solution,  while  the 
other  end  of  the  wire,  with  its  attached  metal,  is  within 
the  other  liquid. — While  upon  seals,  I  may  mention, 
that  their  electrotypes  are  easily  backed  up  with  lead. 
When  fresh  from  the  solution,  let  them  be  varnished 
with  rosin,  dissolved  in  ether,  or  otherwise;  after  which, 
there  will  be  no  difficulty  in  causing  the  adhesion  of  tin 
or  of  soft  solder,  when  required.  Under  other  circum- 
stances, the  best  means  of  tinning  is  to  wash  the  metal 
with  a  solution  of  chloride  of  zinc  and  sal-ammoniac. 
Mr.  Lockey  recommended  stearine  instead  of  rosin. 

56.  Battery  Apparatus. — A  valuable  improvement 
was  devised  in  Russia,  by  Professor  Jacobi,*  and  in 
England  by  a  Member  of  the  Electrical  Society,  Mr. 
Mason.f  It  consists  in  using  a  decomposition  cell, 
analogous  to  that  already  described  (§  11).  The  con- 
stant voltaic  pair  (§  17),  of  copper  and  zinc  is  used 
as  the  generating  cell.  To  the  end  of  the  wire 
attached  to  the  copper  is  fastened  a  plate  of  copper  :  to 
the  end  of  the  wire  attached  to  the  zinc  is  affixed  the 
mould.  The  sheet  of  copper  and  the  mould  are  placed 
face  to  face  in  the  decomposition  cell.  This  arrange- 
ment will  be  better  understood  from  the  annexed  figure. 
A  is  a  cell  of  Daniell's  Battery  (§§  17,  50);  B  the  de- 
composition cell,  filled  with  the  dilute  acid  solution 
of  sulphate  of  copper ;  c  the  sheet  of  copper  to  furnish 


*  Vide  Jacobi' s  Galvano-Plastic. 

f  Vide  Proceedings  of  the  Electrical  Society,  April,  1840,  p. 
203. 


\ 


VOLTAIC  APPARATUS  TO  BE  USED.  49 

a  supply )  m  the  moulds  to  receive  the  deposit.  To 
charge  this,  pour  in  the  several  solutions  :  hang  a  piece 
of  copper  on  the  brass  rod  c;  connect  this  rod  with  the 

Fig,  6. 


copper  of  the  generating  cell  by  the  wire  z  ;  and  the 
other  rod  rn,  with  the  zinc,  by  the  wire  x ;  then,  and 
not  till  then  (§  51),  hang  the  moulds  on  the  rod  m. 

57.  Solutions. — The  solution  used  in  this  decompo- 
sition cell  or  depositing  trough,  greatly  depends  on  the 
battery  or  power  employed ;  with  a  cell  of  Daniell's 
Constant  Battery,  a  solution  of  about  2  sulphate  of 
copper  by  measure,  and  1  acid  water  (1  acid  +  9 
water),  is  undoubtedly  the  best.  When  less  power  is 
employed,  a  little  acid  in  addition  is  found  to  be  advan- 
tageous. 

Professor  von  Kobell,  instead  of  mixing  acid  water 
with  the  saturated  solution  of  sulphate  of  copper,  adds 
solutions  of  Glauber's  salt,  or  of  potash  alum,  or  of 
nitrate  of  potash  j  by  which  means  he  obtains  deposits 
of  very  malleable  copper.  Glauber's  salt  appears  to  be 
5 


50 


ELECTROTYPE  MANIPULATION. 


the  best ;  it  renders  the  solution  more  conductible,  and 
is  not  itself  decomposed  by  such  feeble  currents,  as  are 
here  in  use ;  while  its  solution  will  take  up  as  much 
sulphate  of  copper  as  common  water  does.  Two  of 
saturated  solution  of  sulphate  of  copper,  and  one  of 
sulphate  of  copper  in  solution  of  Glauber's  salt,  are 
stated  to  be  good  proportions. 

To  the  ordinary  solution  of  sulphate  of  copper,  the 
Messrs.  Elkingtons  add  caustic  potash  or  soda  in  small 
quantities,  until  the  precipitate  is  no  longer  redissolved 
by  the  solution,  and  they  thus  obtain  a  solution  for  the 
precipitating  trough  which  gives  up  a  greater  quantity 
of  copper  for  a  given  battery  action,  and  gives  it  up  also 
in  a  less  space  of  time. 

58.  By  an  action  already  illustrated  (§  13),  the  cop- 
per from  the  solution  is  transferred  to  the  mould ;  and 
the  copper  sheet  is  dissolved,  being  converted  with  the 
sulphuric  acid  into  sulphate  of  copper ;  thus  keeping  up 
the  strength  of  the  solution.  The  time  is  somewhat 
longer  by  this  method  :  two  days  will  produce  a  medal 
of  very  good  substance,  firm  and  pliable.  In  speaking, 
however,  of  the  time  required  for  these  experiments,  it 
must  be  borne  in  mind  that  this  depends  much  on  the 
temperature.  If  the  solutions  are  kept  boiling,  a  medal 
may  be  made  in  a  few  hours.  A  single-cell  apparatus 
can  be  readily  treated  thus ;  contrivances  may  easily  be 
devised  for  applying  the  heat  from  a  furnace  or  a  spirit- 
lamp.  In  severe  weather,  the  action  of  the  battery 
almost  ceases.    During  the  severe  winter  of  1840-41, 


VOLTAIC  APPARATUS  TO  BE  USED. 


51 


from  November  to  March,  my  batteries  were  placed 
within  a  few  yards  of  the  fire. 

59.  The  advantages  derived  from  the  introduction  of 
a  decomposition  cell  are  not  limited  to  the  production  of 
single  copies.  Two  or  more  may  be  made  without  any 
further  consumption  of  material  in  the  battery.  If,  for 
instance,  two  cells  be  placed  side  by  side,  and  the  plate 
of  copper  (§  56)  be  placed  in  one,  and  the  mould  (§  56) 
in  the  other :  then,  if  the  two  cells  be  connected  by 
means  of  a  bent  copper  wire,  dipping  into  the  liquid  of 
each,  a  circuit  will  be  completed  for  the  passage  of  the 
voltaic  current.  In  one  cell,  the  copper  plate  will  be 
dissolved  as  before  (§  58),  and  copper  will  be  deposited 
on  one  end  of  the  bent  wire  :  in  the  other  cell,  the  end 
of  that  wire  will  be  dissolved,  and  copper  will  be  de- 
posited on  the  mould.  If  the  bent  wire  is  removed,  and 
a  mould  is  fixed  (§  31),  on  one  end  of  it  to  receive  the 
copper  released  in  the  first  cell,  and  a  plate  of  copper* 
on  the  other  end  to  furnish  a  supply  in  the  second  cell, 
the  one  action  of  the  battery  will  produce  two  medals. 

60.  This  mode  of  proceeding  is  not  confined  to  tak- 
ing merely  two  copies  at  a  time;  it  may  be  extended 
much  further  by  using  more  cells.  Experience  has 
taught  me  that  six  is  a  very  convenient  number.  The 
cells  are  to  be  connected,  each  to  each,  by  bent  wires, 


*  Soldering  is  not  necessary  for  this  purpose ;  let  a  hole  be 
punched  in  the  copper,  and  the  wire  be  passed  through  and 
twisted.  It  is  then  as  well  to  varnish  the  wire  (g  31)  to  pro- 
tect it.  Wires  may  be  united  by  binding  screws,  cleft  sticks, 
or  twisting.  Mk 


52 


ELECTROTYPE  MANIPULATION. 


having  a  mould  on  one  end  and  a  piece  of  copper  on  the 
other.  In  proportion  to  the  number  of  cells  used,  the 
strength  of  the  solution  (§  57)  in  them  must  be  reduced 
by  adding  water,  and  its  conductibiliiy  increased  by 
adding  acid.  It  is  desirable  to  place  the  moulds  and 
the  sheets  of  copper  as  near  together  as  possible,  taking 
care  that  they  do  not  touch.  A  single  pair  of  copper 
and  zinc  in  the  battery  or  generating  cell  (§  56)  will  thus 
produce  a  series  of  six  medals  in  three  days,  if  the  tem- 
perature is  not  much  below  sixty. 

61.  They  who  possess  the  earthenware  troughs  be- 
longing to  the  Wollaston  battery  will  find  the  cells,  on 
account  of  their  shape,  very  convenient  for  this  purpose. 
These  troughs  commonly  contain  twelve  cells.  The 
shape  of  these  cells  permits  the  moulds  and  copper 
plates  to  be  placed  face  to  face,  which,  with  other  pre- 
cautions, insures  an  even  deposit,  and  near  to  each 
other,  which  shortens  the  length  of  liquid  to  be  passed 
through,  and  thus  facilitates  the  operation.  Troughs, 
for  this  purpose,  may  be  made  in  well-varnished  wood, 
of  various  sizes,  and  be  divided  into  cells  by  means  of 
plate  glass  or  glazed  porcelain  partitions.* 

62.  The  advantage  of  this  mode,  in  point  of  economy, 
will  be  manifest,  when  it  is  remembered  that  for  every 
ounce  of  copper  released  from  the  solution  in  the  gene- 


*  Gutta  percha  is  very  valuable  for  forming  cells ;  they  are 
not  costly,  and  possess  many  advantages.  Mr.  Forster's  pro- 
cess of  uniting  gutta  percha  with  wood  for  vessels  of  capacity, 
will  be  found  useful  for  large  cells. 


VOLTAIC  APPARATUS  TO  BE  USED. 


53 


rating  cell,  an  ounce  will  be  deposited  on  each  mould 
(page  25);  and  about  an  ounce  of  zinc  will  be  consumed 
in  effecting  this.  Whether,  therefore,  one  (§  56),  or 
six  (§  60),  or  even  twenty  moulds  be  placed  in  series, 
the  same  quantity  of  zinc  will  be  required.  Hence  an 
ounce  of  zinc  may  be  made  to  furnish  electricity  enough 
to  produce,  according  to  the  will  of  the  experimenter, 
one,  or  six,  or  more  medals,  each  weighing  an  ounce. 

63.  Battery  Apparatus  extended. — Fig.  7  is  an  en- 
graving of  a  DanielFs  battery,  thus  connected  with  a 
series  of  six  cells,  in  each  of  which  is  a  mould.  A,  the 
battery ;  B,  the  trough ;     wire  connecting  copper  plate 


Fig.  7. 


m 

A 

a      cr,       cl       cf.       a  \ 

0 

% 

% 

C  with  the  copper  (§  4)  plate  of  the  battery;  x,  wire 
connecting  mould  m  with  the  zinc  of  battery;  a,  a,  a, 
a,  a,  five  bent  wires,  each  having  a  mould  at  one  end 
and  a  piece  of  copper  at  the  other  (§  31).  A  little 
management  is  requisite  in  charging  this,  in  order  to 
preserve  the  bright  surface  (§  51)  of  the  medals  pro- 

5* 


54 


ELECTROTYPE  MANIPULATION. 


duced.  Charge  the  battery  as  elsewhere  directed;  con- 
nect the  copper  plate  C  with  the  battery;  place  a  wire 
with  its  extreme  ends  dipping  in  the  extreme  cells  of  the 
trough  ;  then,  having  previously  connected  the  zinc  and 
mould  with  the  wire  x}  place  the  zinc  in  the  porous  cell 
and  the  mould  in  its  place  at  m  ;  in  about  two  minutes, 
it  will  be  covered  with  copper;  after  this,  there  is  no 
fear  of  chemical  (§  60)  action;  then  remove  the  end  of 
the  copper  wire  from  the  cell  containing  m,  and  place  it 
in  the  next  cell ;  complete  the  circuit  with  the  bent  wire 
a,  having  a  mould  at  one  end,  and  a  sheet  of  copper  at 
the  other;  after  waiting  a  minute  or  two  for  a  deposit 
of  copper,  remove  the  end  of  the  wire  one  cell  further 
forward ;  and  so  continue  till  the  six  moulds  are  placed 
in. 

64.  I  have  been  in  the  habit  of  rendering  the  elec- 
trotype art  available  in  the  production  of  the  very  ap- 
paratus which  is  destined  to  be  employed  in  the  art; 
and  have  produced  a  compact,  neat,  and  very  simple 
lattery ,  by  the  same  process  by  which  the  battery  thus 
formed  will  produce  copies  of  medals.  I  take  a  large 
jelly-pot,  and,  placing  within  it  some  wax,  stand  it  by 
the  fire  till  the  wax  is  melted  and  the  vessel  thoroughly 
heated ;  then  turn  it  about,  so  that  the  wax  shall  spread 
over  every  part  of  the  interior;  and,  having  done  this, 
pour  away  the  superfluous  wax.  When  cold,  I  rub 
plumbago,  in  the  manner  formerly  described  (§  38),  over 
the  wax  adhering  to  the  sides.  This  vessel  is  then  filled 
with  a  saturated  acid  solution  of  sulphate  of  copper,  and 
in  it  is  placed  a  porous  tube ;  the  tube  is  filled  with  acid 


VOLTAIC  APPARATUS  TO  BE  USED.  55 

water;  a  piece  of  amalgamated  zinc  is  placed  in  the  tube; 
the  wire  attached  to  it  is  bent  over,  and  made  to  press 
upon  the  surface  of  the  plumbago.  In  two  or  three 
hours,  the  whole  of  the  interior  where  the  plumbago  is 
will  be  covered  with  metallic  copper.  The  vessel  will 
now  form  one  of  the  best  and  simplest  generating  or 
battery  cells  that  can  be  constructed  :  this  deposition  of 
copper  forms  the  copper  plate  (§  3)  of  the  voltaic  pair. 
The  plaster  diaphragm  (§  49)  and  the  solutions  will 
complete  the  apparatus.  Or  the  whole  of  the  interior 
surface  might  be  covered  with  plumbago;  and  when, 
after  having  been  used  for  a  week  or  two,  the  deposited 
copper  should  become  thick  enough,  it  might  be  drawn 
out,  or  the  earthenware  cell  might  be  broken  from  it, 
and  thus  a  complete  cell  of  a  Daniell's  battery  (§56) 
might  be  obtained  without  a  seam  or  joint.  To  connect 
a  wire  with  this  coating,  it  is  only  necessary  to  brighten 
the  end,  and  bend  it  so  that  it  shall  press  closely. 

65.  Smee's  Battery. — This  very  useful  source  of  vol- 
#  taic  power  was  named  by  its  inventor,  the  Gliemico-me- 
chanical  Battery.  It  requires  but  one  liquid  for  excit- 
ing it,  namely,  acid  water ;  the  metals  are  amalgamated 
zinc  and  platinized  silver ;  that  is,  silver  on  which  mole- 
cules of  platinum  have  been  voltaically  deposited  in  the 
form  of  a  black  powder.  A  small  quantity  of  the  bi- 
chloride of  platinum  is  mixed  with  acid  water,  and  the 
solution  is  decomposed  by  the  use  of  a  platinum  terminal 
in  connection  with  the  copper  of  the  battery,  and  the 
substance  to  be  platinized  in  connection  with  the  zinc, 
A  few  minutes'  action  will  suffice.    Platinum  is  some- 


56 


ELECTROTYPE  MANIPULATION. 


times  platinized;  but,  for  all  practical  purposes,  silver 
is  equally  serviceable.  This  aggregation  of  small  points 
facilitates  the  liberation  of  the  evolved  hydrogen,  which 
escapes  with  a  loud  hissing  noise,  in  place  of  adhering 
to  the  metal  and  interrupting  the  action.  The  arrange- 
ment is  generally  made  with  one  platinized  silver  plate 
between  two  zinc  plates,  as  in  the  following  figure,  where 
s  is  the  silver  plate  connected  with  the  copper  of  the 
usual  decomposition  cell,  and  z  the  zinc  plate  connected 
with  the  moulds.  In  employing  this  arrangement,  care 
must  be  taken  to  avoid  dropping  any  sulphate  of  copper 
into  the  acid  water ;  for  the  copper  would  at  once  be 
reduced  upon  the  silver  plate,  and  by  altering  the  nature 
of  the  battery  would  spoil  it. 


66.  As  the  silver  plate  in  this  arrangement  is  between 
the  zinc  plates,  it  follows  that  the  streams  of  hydrogen 
must  ascend  between  the  metals  of  the  pair,  so  that, 
while  in  one  sense  they  form  a  partial  screen  between 
the  plates,  they,  on  the  other  hand,  prevent  the  plates 


VOLTAIC  APPARATUS  TO  BE  USED.  57 

being  approximated  within  certain  limits.  A  very  in- 
genious modification  of  this  arrangement  has  been 
devised  by  Professor  Grove,*  who  substitutes  platinized 
silver  gauze  in  place  of  the  plate  of  silver  ;  as,  by  this 
means,  a  facility  is  afforded  to  the  hydrogen  of  passing 
through  the  apertures  of  the  gauze,  and  making  its 
escape  at  the  outer  side  instead  of  between  the  two 
plates,  the  latter  may  be  brought  much  closer  together, 
without  having  the  action  intercepted  by  the  presence 
of  the  liberated  and  escaping  hydrogen. 

67.  New  Electrotype  Battery. — As  it  is  no  easy 
matter  to  obtain  silver  gauze,  I  advise  the  following 
substitute,  which  has  its  peculiar  advantages  :  Take  a 
sheet  of  cleaned  (§  98)  copper  gauze,  of  the  exact  size 
required  (for  it  must  not  be  cut  afterwards),  and  affix 
to  it  permanently  the  binding  screw  or  wire,  which  is  to 
be  employed  afterwards  in  making  connections.  Place 
it  then  in  a  decomposition  cell,  containing  sulphate  of 
copper,  and  submit  each  side  to  the  action  of  the  bat- 
tery, until  a  bright  deposit  of  pure  copper  is  thrown 
down,  of  sufficient  thickness  to  coat  all  the  wires,  and 
to  unite  them  permanently  into  one.  Then  remove  and 
wash  it  in  boiling  water.  After  which,  electro-plate  it 
by  the  means  to  be  described  in  Part  II.  A  piece  of 
copper  gauze,  thus  prepared,  will  be  even  better  fitted 
for  the  desired  purpose,  than  if  it  were  of  silver  wire ; 
for  the  deposition  of  copper  on  it,  and  then  plating  this 
deposit,  will  have  advanced  one  great  step  towards 


*  Vide  Proceed.  Elec.  Soc.  p.  117.— Sept.  21,  1841. 


58 


ELECTROTYPE  MANIPULATION. 


altering  the  character  of  the  surface;  and  producing 
one  better  fitted  to  throw  off  the  hydrogen.  The  opera- 
tion will  be  completed  by  platinizing  according  to  the 
directions  given  above. 

68.  In  the  illustration  of  the  platinized  battery 
(§  65),  the  metals  are  represented  parallel  and  per- 
pendicular;  in  the  present  arrangement  there  must  be 
but  one  zinc  plate,  and  the  zinc  and  gauze  must  be 
very  near  to  each  other,  but  must  deviate  a  few  degrees 
from  the  perpendicular ;  and  in  such  a  direction  that 
the  platinized  gauze  shall  be,  as  it  were,  uppermost. 
For,  as  the  gas  finds  its  way  to  the  surface  in  perpen- 
dicular lines,  such  a  disposition  of  the  arrangement 
will  at  once  admit  it  to  pass  through  the  interstices  of 
the  gauze,  and  readily  to  escape  by  the  desired  channel 
— the  outside  of  the  gauze.  A  better  mode  of  con- 
structing the  apparatus  is  to  employ  a  gauze  on  each 
side  of  the  zinc.  In  this  case,  the  zinc  must  be  perpen- 
dicular •  and  the  gauze  not  exactly  parallel,  but  rather 
closer  at  the  top  than  below.  The  difficulty  of  obtain- 
ing copper  gauze  led  to  the  production  of  electro-lace, 
which  was  first  suggested  and  made  for  this  kind  of 
battery  by  Mr.  Phillips  of  St.  Austell. 

69.  Electro-Lace. — A  piece  of  lace  is  stretched  on  a 
frame,  and  well  rubbed  with  warm  wax  :  it  is  then  held 
to  the  fire  to  effect  its  saturation  with  wax,  and  is 
placed  afterwards,  and  while  hot,  between  two  pieces  of 
blotting  paper  in  order  to  remove  the  wax  from  the  pat- 
tern ;  or  it  may  be  saturated  with  varnish.  It  is  then 
plumbagoed  and  treated  as  an  ordinary  mould.    A  few 


VOLTAIC  APPARATUS  TO  BE  USED.  59 

hours'  action  will  so  deposit  metal  on  it  as  to  present 
the  character  of  a  perfect  conversion  into  copper.  This 
may  be  plated,  and  then  platinized. 

70.  Constant  Acid  Battery. — Since  the  appearance 
of  the  first  edition  of  this  work,  I  have  been  employ- 
ing, with  slight  modification,  an  ordinary  acid  battery, 
namely,  a  chemico-mechanical  battery,  in  which  rough- 
ened copper  is  used  instead  of  platinized  silver ;  and  I 
find  it  admirably  adapted  to  the  purpose  of  electrotype. 
Other  circumstances  being  the  same,  it  requires  nearly 
twice  the  time  of  a  sulphate  battery ;  but  this  is  in  a 
degree  compensated  by  the  fineness  of  the  deposit  ob- 
tained, and  the  trifling  expense  attending  its  use. — The 
interior  of  a  jar  is  coated  with  copper  (§  67),  and  the 
action  is  continued  until  the  solution  employed  for  this 
purpose  is  nearly  exhausted.  By  this  means,  the  sur- 
face of  the  copper  obtained  presents  an  infinite  number 
of  small  points,  which  very  readily  part  with  the  hydro- 
gen. The  principle  is  precisely  that  developed  by  Mr. 
Smee,  and  brought  to  practice  in  his  platinized  battery. 
— This  arrangement  may  be  adopted  without  the  use  of 
diaphragms.  Amalgamated  zinc  is  employed.  I  find 
that  this  kind  of  battery,  variously  arranged,  is  greatly 
used  in  the  arts.  Sometimes  a  single  battery  is  suffi- 
cient; at  other  times,  a  series  of  two,  three,  or  four, 
having  the  zinc  of  one  connected  with  the  copper  of  the 
next;  as  in  Fig.  9. — I  have  myself  been  of  late  operating 
with  this  battery  on  a  large  scale,  using  surfaces  of  from 
10  to  14  square  feet :  if  the  copper  surface  has  been 
exposed  to  the  air  for  any  time,  while  the  battery  is  out 


60 


ELECTROTYPE  MANIPULATION. 


of  use,  it  should  be  well  washed  with  acid  water,  or  the 
old  solution  of  zinc,  before  using  it  again,  in  order  to 
remove  any  oxide  of  copper  that  may  be  there.  Under 


these  circumstances,  I  have  every  reason  to  be  satisfied 
with  its  action,  and  to  prefer  it,  from  its  simplicity  and 
steady  action,  to  any  other  form. 

71.  Prince  Bagration's  Battery. — A  pan  is  filled 
with  earth,  which  is  then  saturated  with  a  solution  of 
sal-ammoniac  ;  a  copper  plate,  having  been  first  wetted 
with  solution  of  sal-ammoniac,  and  then  exposed  to  the 
air  until  a  green  film  is  formed,  is  thrust  into  the  pan  of 
earth  ;  and  opposite  to  it  is  thrust  a  zinc  plate.  Prof. 
Jacobi  speaks  favorably  of  this  source  of  a  constant 
power  for  the  reduction  of  metals. 

72.  The  Earth  a  Battery. - — When  slow  actions  are 
required,  the  moisture  of  the  earth  itself  may  be  made 


VOLTAIC  APPARATUS  TO  BE  USED. 


61 


a  source  of  power ;  all  that  is  necessary  being  to  bury 
in  it  large  plates  of  zinc  and  copper.  The  native  moist- 
ure of  the  soil  constitutes  the  exciting  liquid. 

73.  Decomposition  Cells  may  be  constructed  of  all 
sizes,  according  to  circumstances,  of  wood,  protected 
with  varnish,  or  other  compounds  impervious  to  water. 
Two  parallel  wires  are  secured  along  the  top ;  one  is  to 
be  connected  with  the  zinc,  and  the  other  with  the  cop- 
per of  the  battery.  On  the  former  are  hung  the  moulds, 
by  merely  bending  the  wires  attached  to  them  into  a 
hook ;  and  on  the  latter  is  hung  a  sheet  of  copper.  These 
wires  may  be  placed  nearer  to  each  other,  as  circum- 
stances require.  By  this  means,  several  medals  may  be 
made  at  the  same  time.  This  arrangement  is  most 
commonly  adopted;  it  does  not  of  course  economize  the 
zinc,  as  described  in  a  former  place  (§  62).  One  ounce 
of  zinc  produces  six  or  more  medals,  not  weighing  each, 
but  all  together  an  ounce. 

74.  The  deposited  metal  will  present  various  thick- 
nesses, according  to  the  relative  position  of  the  mould 
and  the  plate  of  copper;  if  they  are  face  to  face,  and 
parallel,  the  thickness  will  be  uniform,  or  nearly  so; 
generally  speaking,  the  copper  on  the  lower  part  of  the 
mould  is  thicker  than  that  on  the  higher :  this  occurs 
from  the  specific  gravity  of  the  sulphuric  acid,  used  to 
render  the  liquid  conductible,  determining  it  in  a  mea- 
sure toward  the  bottom  of  the  cell,  rendering  the  lower 
part  of  the  liquid  more  conductible  than  the  upper.  To 
cause  a  more  uniform  distribution,  it  is  better  to  stir  the 
liquid  occasionally.    But  in  many  cases  it  is  advisable 

6 


62 


ELECTROTYPE  MANIPULATION. 


to  have  a  flat  trough,  as  in  the  annexed  sketch,  and  to 
place  the  mould  below  and  the  copper  plate  above.  With 
large  casts,  and  those  in  deep  relief,  this  is  absolutely 


Fig.  10. 


necessary;  for  without  it  a  uniform  thickness  in  the  de- 
posit is  next  to  impossible,  and  the  solution  within  the 
recesses  of  the  mould,  being  unable  to  ascend  and  inter- 
change itself  with  the  rest,  as  it  becomes  exhausted  of 
metal,  soon  gives  a  brittle  deposit,  and  finally  no  de- 
posit at  all.  My  largest  trough,  which  will  contain 
upwards  of  a  hundred  gallons  of  solution,  is  of  this 
form,  and  is  lined  with  a  mixture  of  asphalte  and  rosin. 
Mechanical  arrangements  keep  the  mould  sunk,  until  the 
deposited  metal  is  itself  heavy  enough  for  the  purpose. 
The  copper  plate  is  removed  once  or  twice  a  day  and 
washed,  to  prevent  defiling  the  cast  with  the  impurities 
of  the  metal. 

In  order  to  hasten  the  thickening  of  the  deposit, 
Professor  Jacobi  has  recommended  that  copper  filings 
be  occasionally  sifted  upon  the  electrotype;  and  when 
one  batch  of  filings  have  become  incorporated  with  the 


MANAGEMENT  OF  MOULDS. 


63 


solid  metal,  by  means  of  the  reduced  copper,  he  advises 
other  siftings  to  be  made :  and  so  on. 

75.  Management  of  the  Moulds. — Thus  much,  then, 
with  respect  to  the  construction  of  moulds,  and  the  nature 
and  various  forms  of  the  voltaic  apparatus.  From  what 
has  been  said,  the  reader  will  be  able  to  make  his  own 
selection,  according  to  circumstances;  he  will  see  the 
capabilities  of  the  several  processes,  and  adopt  the  one 
best  suited  to  his  particular  purpose.  It  remains  now  to 
give  a  few  special  directions  in  reference  to  the  manage- 
ment of  moulds,  and  of  the  voltaic  apparatus  generally. 
The  copper  solution  will  act  chemically  on  the  fusible 
metal,  if  the  mould  is  placed  in  it  before  the  battery  is 
in  action,  and  will  produce  on  its  surface  a  dirty,  dark 
deposit.  To  guard  against  this,  it  is  necessary  that 
everything  should  be  arranged  before  the  mould  is  placed 
in  the  situation  allotted  to  it  (§  51).  The  circuit  should 
be  completed  by  immersing  the  mould  last.  With  this 
precaution,  the  immersion  of  the  mould,  if  of  metal,  will 
be  followed  by  an  instant  deposit  of  copper  on  its  whole 
surface ;  after  which  there  is  no  fear  of  the  oxide.  A 
circumstance  no  less  strange  than  true  in  these  experi- 
ments, is,  that  the  surface  of  a  fusible  mould  thus  man- 
aged is  never  wetted  by  the  liquid  in  which  it  is  placed ; 
in  fact,  it  never  comes  into  actual  contact  with  the  liquid ; 
its  immersion  in  the  liquid  and  its  receiving  a  coating 
of  copper  are  simultaneous ;  the  one  is  the  instantane- 
ous cause  of  the  other.  When  the  copy  is  removed,  the 
mould  is  as  bright  and  as  dry  as  when  first  made. 

76.  The  deposition  of  the  copper  on  the  plumbagoed 


64 


ELECTROTYPE  MANIPULATION. 


surface  (§  39)  of  the  wax  moulds,  is  not  thus  instantane- 
ous. The  film  of  conducting  substance  with  which  they 
are  coated  being  very  thin,  and  not  continuous,  the  ope- 
ration is  a  step  by  step  process  from  particle  to  particle. 
The  deposition  of  copper  is  gradual:  it  commences  in 
the  neighborhood  of  the  wire  attached  to  them,  and 
spreads  gradually  over  the  remaining  portion.  These 
moulds  do  become  wetted,  and  the  medals  obtained  from 
them  often  come  off  with  dirty  surfaces ;  the  medals  also 
bring  with  them  the  whole  or  part  of  the  plumbago,  and 
hence  the  moulds,  if  not  damaged,  require  a  fresh  coat 
of  this,  before  they  are  used  again.  These  dirty  speci- 
mens may  be  very  readily  cleaned,  if  required ;  the  mode 
will  be  described  in  the  sequel.  The  production  of  dirty 
medals  is  the  least  evil  arising  from  the  use  of  plumba- 
goed  moulds ;  there  is  one  of  far  greater  importance — 
one  which  requires  some  attention  to  escape.  As  the 
deposition  of  copper,  which  is  gradually  diffused  over  the 
whole  surface,  commences  at  one  point  contiguous  to  the 
connecting  wire,  it  follows  that  the  power  of  the  battery 
at  the  first  is  concentrated  in  a  small  space.  The  con- 
sequence of  this  will  be,  that,  unless  means  be  taken  to 
avert  it,  hydrogen  will  be  evolved  with  the  copper  at 
first,  decreasing  in  quantity  till  enough  of  the  mould  is 
covered  with  a  film  of  copper  to  increase  the  size  of  the 
surface  to  the  requisite  standard  for  releasing  copper  alone, 
after  this  all  things  go  on  well ;  but  it  is  invariably 
found  that  the  portion  near  the  wire,  from  the  irregu- 
larity of  the  primitive  deposit,  is  rotten  or  very  brittle. 
To  prevent  this,  I  always  begin  by  placing  a  wire  in  lieu 


MANAGEMENT  OF  APPARATUS. 


65 


of  a  plate,  opposite  the  plumbagoed  mould,  in  the  de- 
composition cell ;  this  reduces  the  power  of  the  battery 
or  the  quantity  of  electricity  passing  :  as  the  copper 
deposits,  I  immerse  the  wire  to  a  greater  depth,  and 
when  the  mould  is  partially  covered  with  copper,  I  re- 
move the  wire,  place  in  the  copper  plate,  and  leave  the 
experiment  with  the  assurance  of  a  successful  result. 
But  moulds  furnished  with  guiding-wires  (§  39)  may 
be  put  into  the  decomposition  cell  without  the  precau- 
tion of  using  a  wire  first,  instead  of  a  plate,  as  above 
suggested.  It  will  occasionally  occur  in  wax  moulds, 
and  sometimes  in  fusible  metal  moulds  of  very  elabo- 
rately executed  medals,  that  bubbles  of  air  remain  in  some 
of  the  complicated  interstices;  these  must  be  removed, 
or  the  result  will  be  infallibly  disfigured.  They  are  re- 
moved by  lightly  brushing  the  surface  of  the  mould  with 
a  feather,  immediately  after  it  is  immersed  in  the  liquid. 
If  it  should  seem  that  any  part  of  the  mould  is  not  suffi- 
ciently coated  with  plumbago,  it  may  be  removed  from 
the  solution,  washed  with  water,  dried  with  blotting- 
paper,  and  again  rubbed  with  plumbago.  This  will 
sometimes  save  it,  although  generally  such  a  condition 
of  things  announces  a  failure. 

77.  Management  of  the  Battery  Apparatus. — The 
electrotypist,  who  expects  to  find  all  his  experiments 
going  on  favorably,  will  be  often  grievously  disappointed : 
with  the  best  intentions  and  the  most  careful  arrange- 
ments he  may  sometimes  fail.  For,  after  having  observed 
all  the  directions  hitherto  given,  his  battery  may  have 
too  little  work  to  do,  or  too  much;  and  this  can  only  be 

6* 


66 


ELECTROTYPE  MANIPULATION. 


determined  by  experience,  and  by  attention  to  the  prin- 
ciples laid  down  in  this  book.  The  former  will  produce 
the  dark  powder,  elsewhere  mentioned  (76);  the  latter 
a  hard,  red,  brittle  deposit,  or  a  heap  of  crystals.  The 
terms  too  much  and  too  little  are  here  used  in  a  very 
general  sense,  and.  will  be  better  understood  by  describ- 
ing the  causes,  the  results,  and  the  mode  of  rectifying 
these  irregularities. 

78.  If  the  battery  is  too  large,  or  the  copper  plate  in 
the  decomposition  cell  is  too  large;  or  if  the  mould  is 
too  small,  hydrogen  as  well  as  copper  will  be  released, 
and  the  deposit  will  be  the  dark  powder ;  the  same 
will  occur  if  the  solution  in  the  decomposition  cell  con- 
tains too  mrach  acid  or  too  little  sulphate  of  copper.  To 
rectify  this,  the  battery  may  be  made  smaller  by  pour- 
ing out  some  of  the  solution,  and  so  exciting  less  of  its 
surface ;  or  a  smaller  copper  plate  may  be  used  in  the 
decomposition  cell ;  or  crystals  of  sulphate  of  copper 
may  be  thrown  into  the  liquid  contained  therein ;  or 
the  copper  plate  and  mould  may  be  removed  far  apart ; 
or  a  fine  wire  may  be  interposed  between  the  mould  and 
the  wire  connecting  it  with  the  battery.  Each  or  all  of 
these  alterations  may  be  made  according  as  circum- 
stances or  convenience  shall  dictate ;  a  few  days'  expe- 
rience will  be  better  than  pages  of  instruction. 

79.  If  the  battery  is  too  small,  or  the  copper  plate  in 
the  decomposition  cell  too  small ;  or  if  the  mould  is  too 
large,  or  if  the  decomposition  cell  contains  too  little  acid 
or  too  much  sulphate  of  copper,  or  if  the  weather  be  too 
cold,  the  copper  will  be  deposited  very  slowly,  and  will 


MANAGEMENT  OF  APPARATUS. 


67 


present  a  dull  red  exterior,  and  be  of  a  very  brittle  tex- 
ture ;  or  will  be  thrown  down  in  a  crystalline  form. 
The  alterations  necessary  to  rectify  this  defect  will 
readily  suggest  themselves. 

80.  The  medium  between  these  two  conditions  for- 
tunately has  a  very  wide  range,  so  that  the  chances  of 
avoiding  the  two  extremes  are  greatly  in  favor  of  the 
experimenter.  The  lines  of  demarcation  within  which 
the  proper  deposit  is  obtained,  are,  as  may  be  imagined, 
not  precisely  denned.  And  hence  the  deposited  metal 
possesses  various  gradations  of  character,  according  to 
the  circumstances  under  which  it  is  obtained.  When 
all  things  are  going  on  well,  if  the  mould  be  lifted  out* 
of  the  solution,  it  will  present  a  brilliant,  light,  copper- 
colored  surface  :  this  characteristic  can  scarcely  be  mis- 
taken after  it  is  once  seen. 

81.  In  addition  to  this,  the  following  general  ob- 
servations on  the  theory  of  deposits,  may  be  ac- 
ceptable :  "It  was  thought  that  the  rotten  deposit 
—a  characteristic  with  which  all  those  who  are  but  just 
initiated  into  the  art  are  familiar — results  from  the 
presence  of  the  sulphate  of  zinc  among  the  sulphate  of 
copper  .  .  .  The  real  cause  depends  on  the  relation 
subsisting  between  the  generating  power,  dependent  on 
the  action  between  the  zinc  and  the  acid,  and  the 
strength  of  the  solution  of  the  sulphate  of  copper,  on 
which  this  power  is  exercised.    If  the  latter  is  well 


*  The  mould  may  be  removed  with  impunity,  after  it  is  well 
coated  with  metal. 


68 


ELECTROTYPE  MANIPULATION. 


saturated,  the  copper  will  be  released  pure  and  firm ;  if 
it  is  almost  exhausted,  the  hydrogen  gas  will  be  released 
with  the  copper,  and  the  deposit  will  be  a  dull  powder. 
In  the  wide  range  between  these  two  states  is  found  the 
brittle  deposit :  it  appears  under  many  varieties  of 
forms,  according  as. the  solution  is  nearer  to  a  state  of 
saturation  or  to  one  of  exhaustion  on  the  one  hand ;  or 
according  to  the  energy  or  weakness  of  the  affinity  be- 
tween the  zinc  and  its  exciting  solution  on  the  other. 
This  latter  condition  exists  in  a  modified  form,  when  a 
large  piece  of  zinc  is  used  with  a  small  object  to  be 
copied.  The  deposit  is  very  hard,  but  not  tenacious. 
It  may  be  easily  broken.  In  copying  seals,  and  such 
like  small  objects,  little  pieces  of  zinc  an  inch  square 
are  quite  large  enough." 

82.  The  medals  are  removed  from  the  fusible  moulds 
by  gradually  raising  the  edges  with  a  pointed  instru- 
ment, a  brad-awl,  for  instance,  and  then  using  it  lever- 
fashion  to  raise  the  medal  out  of  the  mould.  Care  must 
be  exercised  in  this,  for  the  contact  between  the  two  is 
so  close  that  the  force  occasionally  required  may  cut 
the  medallion.  The  separation  from  the  wax-moulds 
requires  no  force,  they  are  laid  face  downwards  on  a 
table,  and  after  pressing  the  slight  overlapping  edge  of 
copper  with  the  brad-awl,  in  different  parts  of  the  cir- 
cumference, the  two  may  be  pulled  apart. 


BRONZING. 


G9 


IV.—BKONZING. 

83.  If  proper  precautions  are  taken,  the  medals  from 
the  fusible  moulds  will  generally  present  a  bright  copper 
surface  ;  occasionally,  however,  they  will  present  a  very 
brilliant  surface,  greatly  resembling  silver.  When  this 
is  the  case  they  may  be  placed,  without  further  trouble, 
for  the  cabinet.  The  silvery  tint  is  only  obtained  on 
first  specimens  :  it  would  seem  that  the  surface  of  the 
new-made  mould  is  covered  with  a  metallic  film,  which 
attaches  itself  firmly  to  the  surface  of  the  deposited  cop- 
per. It  is  so  firmly  attached,  that  it  may  be  polished 
with  a  leather  or  plate  brush,  without  sensibly  affecting 
it.  If  specimens  of  this  description  are  exposed  to  the 
air,  they  will  occasionally  require  the  application  of  the 
plate-brush  to  restore  their  primitive  brilliancy. 

84.  Chemical  Bronze. — There  are  many  modes  of 
bronzing  employed  in  the  arts ;  the  intent  of  each  is  to 
bring  out  the  workmanship  of  the  object.  The  selection 
is  entirely  a  matter  of  taste.  To  prevent  too  great  a 
sameness  of  appearance  in  a  cabinet,  it  is  perhaps  better 
not  to  confine  one's  self  to  a  solitary  method. — A  chemi- 
cal bronze  may  be  made  by  boiling  two  ounces  of  car- 
bonate of  ammonia  with  one  ounce  of  acetate  of  copper 
in  half  a  pint  of  vinegar,  till  the  vinegar  is  nearly  evap- 
orated. Into  this,  pour  a  solution  consisting  of  sixty- 
two  grains  of  muriate  of  ammonia,  and  fifteen  grains 
and  a  half  of  oxalic  acid,  in  half  a  pint  of  vinegar. 
Replace  the  vessel  on  the  fire  till  the  contents  boil : 


70 


ELECTROTYPE  MANIPULATION. 


when  cold,  strain  through  filtering  paper ;  preserve  the 
liquor  for  use.  The  remaining  sediment  may  be  again 
treated  with  another  half  pint  of  the  solution.  This 
preparation  must  only  be  applied  to  medals  perfectly 
bright  and  clean. 

85.  Dirty  specimens  may  be  polished  by  an  article 
used  in  domestic  economy,  consisting  of  rotten-stone, 
soft  soap,  and  water;  the  medal  is  to  be  well  rubbed 
with  a  hard  brush  dipped  in  this.  Care  must  be  taken 
not  to  scratch  the  medal.  It  must  afterwards  be  wash- 
ed in  water  and  placed  to  dry ;  when  dry,  the  applica- 
tion of  the  leather  and  plate  brush  will  produce  the  re- 
quired polish.  Medals  may  also  be  cleaned  by  dipping 
them  for  a  few  seconds  in  nitric  acid,  either  concen- 
trated or  diluted;  wax  and  grease  may  be  removed  by 
boiling  in  pearlash  and  water,  or  by  pouring  the  boil- 
ing lye  on  the  medals ;  or  by  washing  with  turpentine. 
Cleansing  processes  will  be  more  fully  described  in  the 
Second  Part,  when  we  come  to  electro-gilding  and 
plating,  in  which  they  are  of  prime  importance. 

86.  In  applying  the  bronze,  first  warm  the  medal, 
then  dip  a  earner s-hair  pencil  into  the  liquor  (§  84), 
and  brush  the  surface  for  half  a  minute  ;  immediately 
after,  pour  boiling  water  over  it ;  directly  the  medal  is 
dry,  rub  its  surface  lightly  with  soft  cotton,  very 
slightly  moistened  in  linseed  oil :  gentle  friction  with  a 
piece  of  dry  cotton  will  finish  the  operation.  The  color 
produced  by  this  means,  is  red ;  its  tint  varies  accord- 
ing to  circumstances.  Medals  bronzed  thus  must  be 
examined  occasionally  before  they  are  consigned  to  the 


BRONZING. 


71 


cabinet ;  for  if  perchance  the  vinegar  has  not  been  per- 
fectly washed  away,  they  will  be  disfigured  by  the  forma- 
tion of  a  green  powder — the  acetate  of  copper.  Should 
this  occur,  it  may  be  removed  by  means  of  the  moist 
and  dry  cotton. 

87.  Black-Lead  Bronze. — A  very  beautiful  bronze  is 
obtained  by  the  simple  application  of  plumbago  ;  it  is 
obtained  in  a  few  minutes,  and  with  very  little  trouble. 
The  tint  obtained  seems  very  much  to  depend  on  the 
condition  of  the  surface  of  the  original  medal ;  copies 
of  some  medals  "  take  "  the  black-lead  better  than  those 
of  others.  To  produce  the  tint  in  the  greatest  perfec- 
tion, the  operation  should  be  performed  immediately 
after  the  medal  is  separated  from  the  mould.  Briglit 
specimens  from  fusible  moulds  are  best,  but  all  others 
may  be  thus  treated ;  those  taken  from  wax  should  be 
cleaned  with  pearlash  or  soda. 

88.  The  bronze  is  obtained  by  brushing  the  surface 
of  the  medal  with  plumbago  ;  then  placing  it  on  a 
clear  fire  till  it  is  made  too  hot  to  be  touched,  and 
applying  a  plate-brush  as  soon  as  it  ceases  to  be  hot 
enough  to  burn  the  brush.  A  few  strokes  of  the  brush 
will  produce  a  dark  brown  polish,  approaching  black, 
but  entirely  distinct  from  the  well-known  appearance  of 
black-lead.  If  the  same  operation  is  performed  on  a 
medal  that  has  been  kept  some  days,  or  upon  one  that 
has  been  polished  (§  85),  a  different  but  very  brilliant 
tint  is  produced.  The  color  is  between  red  and  brown. 
The  richness  of  color  thus  produced  is  by  many  pre- 
ferred to  the  true  dark  brown. 


72 


ELECTROTYPE  MANIPULATION. 


89.  Carbonate  of  Iron  Bronze. — Very  beautiful  tints 
are  produced  by  using  the  substance  commonly  known 
as  plate-powder,  or  rouge ;  after  moistening  it  with 
water  it  is  applied  and  treated  precisely  in  the  same 
manner  as  the  plumbago.  Some  care  and  practice  are 
required  in  its  use,  lest  it  should  stain  instead  of  bronze 
the  medal. — I  have  received  from  the  publishers  of 
this  book  a  specimen  of  bronze  superior  to  any  I  have 
elsewhere  met  with.    It  leaves  nothing  to  be  desired. 

■ — Should  an  experiment  fail,  the  several  bronzes  may, 
in  many  cases,  be  removed,  and  the  attempt  can  be 
repeated. 

90.  Mounting  the  Medals. — I  have  adopted  a  method 
of  mounting  the  medals  obtained  from  the  fusible 
moulds  (§  20),  which  gives  a  finish  to  their  appearance. 
I  obtain  pale  green  cards,  the  size  of  visiting  cards ; 
and  cut  some  of  these  into  single  squares ;  the  width  of 
the  card  being  the  side  of  the  square ;  others  into 
smaller  squares,  half  the  length  of  the  card  forming  the 
side  of  the  square.  A  pencil  circle  is  drawn  the  size  of 
the  medal;  and  two  ink  circles  in  order  to  "  throw' ' 
the  medal  "  forward."  The  part  within  the  pencil 
circle  is  cut  out ;  and  waste  cards  are  cut  to  fit  the  extra 
edge  of  the  medal.  The  two  cards  being  fixed  together 
with  very  strong  gum  water,  the  medal  is  placed  in, 
and  secured  by  another  card  gummed  on  at  the  back. 
The  obverse  and  reverse  are  then  gummed  back  to  back, 
and  thus  the  appearance  of  a  perfect  and  solid  medal  is 
produced,  equal,  in  point  of  workmanship  and  beauty, 
to  the  original.    To  hold  the  cards  together  until  the 


CONCLUDING  OBSERVATIONS. 


73 


gum  dries,  I  use  cleft-sticks.  The  medals  obtained  from 
wax  moulds,  having  no  addition  to  the  edges,  are  not 
well  fitted  to  be  mounted  thus  :  they  may  simply  have 
any  roughness  removed  from  their  edges  with  a  sharp 
file,  and  be  placed  in  the  cabinet  without  being  fitted 
with  cards. 

V.— CONCLUDING  OBSERVATIONS. 

91.  Having  now  gone  systematically  through  the 
process  of  working  in  copper,  by  means  of  the  voltaic 
current,  halting  here  and  stepping  aside  there,  in  order 
to  make  all  things  as  clear  as  possible;  and  having 
fulfilled  my  promise  (§  1)  of  leading  the  reader  "  from 
the  original  medal  to  the  perfect  copy,  ready  for  the 
cabinet  ff  I  trust  he  is  in  a  condition,  so  far  as  these 
instructions  are  concerned,  to  go  from  small  things  to 
great,  and  by  increasing  the  size  of  his  apparatus,  as 
it  shall  seem  good  to  him,  to  carry  out  on  the  large 
scale  what  he  has  here  been  taught  to  do  on  the  small. 
I  now,  therefore,  refer  him  to  Part  II.,  in  which  the 
manipulation  with  gold  and  silver,  and  other  metals 
and  alloys  of  metals,  will  be  detailed ;  and  all  and  sun- 
dry the  leading  applications  and  the  extensive  ramifica- 
tions of  the  art  will  be  set  before  him. 


7 


INDEX. 


Acid  battery,  constant,  \  70. 
Affinity,  elective,  electro-chemical,  \  4. 
Air-bubbles  to  be  removed,  g  76. 
Amalgamation  of  zinc,  $  46. 

Battery  for  works  on  a  large  scale,  \  70. 

  Prince  Bagration's,  §  71. 

 produced  by  the  electrotype  process,  \  70. 

  the  earth  as  a,  \  72. 

  too  large,  \  78. 

  too  small,  \  79. 

  without  acid  or  mercury,  \  53. 

Black-lead  for  wax  moulds,  §  37. 
Brittle  copper,  mode  of  avoiding,  $  77. 
Bronze,  carbonate  of  iron,  \  89. 

 Knight's,  \  89. 

  chemical,  §  84. 

 application  of,  \  86. 

  plumbago,  §  87. 

Charcoal,  or  carbon,  for  negative  plate,  \  5. 
Chemical  action,  ordinary,  cause  of,  \  46. 
Chemical  effects,  ordinary,  \\  7,  18. 
Chemico-mechanical  battery,  \  65. 
Cleaning  electrotype  medals,  \  85. 


7G 


INDEX. 


Clichee  moulds,  §  26. 
Constant  battery,  H  18,  56,  &c. 

Copper  in  good  condition,  chances  in  favor  of  depositing,  \  80. 
 irregularity  in  the  deposition  of,  \  74. 

Daniell's  constant  battery,  \\  18,  56. 
Decomposition  cell,  \\  43,  73. 
 flat,  I  74. 

 introduction  of,  for  electrotype,  g  56. 

 of  sulphate  of  copper,  \\  12,  13. 

 of  water,  g  11. 

Diaphragms,  brown  paper,  §  44. 

 membrane,  \  48. 

 pipe-clay,  \  48. 

 plaster  of  Paris,  \  49. 

Elastic  moulds,  \  42. 

Electrical  equilibrium,  disturbance  of  the,  \  6. 
Electro-chemical  equivalents,  page  14,  \  51. 
Electro-lace,  §  69. 
Electrolysis,  description  of,  §  10. 
Electrotype,  §  14. 

 facility  of  practising,  \  15. 

 minutely  correct  in  copying,  \  24. 

Filings  for  thickening  casts,  §  74. 
Flame  from  charcoal  points,  page  23. 
Flowers,  mode  of  copying,  $  39. 
Fused  compounds  decomposed,  page  24. 
Fusible  metal  for  smaller  medals,  §21. 
 ingredients  in,  \  22. 

Gauze  for  battery  plate,  \  66. 
Generating  cell,  §  43. 
Glass,  how  to  coat,  g  41. 


INDEX. 


77 


Glauber's  salt  to  give  conducting  power,  \  37. 
Guiding-wires,  \\  39,  76. 
Gutta  Percha  moulds,  \  42. 

Heating  power  of  batteries,  page  24. 
Hydrogen  released  at  the  copper  plates,  $  4. 
 released  with  the  copper,  §  78. 

Insects,  mode  of  copying,  \  39. 

Iodide  of  potassium,  decomposition  of,  page  24. 

Medals  to  be  cold  for  use,  \  24. 

Metals  released  at  negative  end  of  voltaic  pairs,  \  14. 
Moulds,  elastic,  \  42. 

 gutta  percha,  \  42. 

 made  in  parts,  \  41. 

 management  of,  \  75. 

 of  fusible  metal  not  wetted  by  the  liquid,  g  75. 

 preparation  of,  page  26. 

Mounting  electrotype  medals,  mode  of,  $  90.  . 
Muriate  of  ammonia  for  batteries,  |  53. 

Names  given  to  the  art  of  copying  by  voltaic  electricity,  \  2. 
Negative  end  of  the  battery,  which  is  the,  \  8. 

Oxygen  released  at  the  positive  plate,  \  4. 

Phosphorous  solution  for  flowers,  &c,  §  39. 
Physiological  effects  of  Voltaic  electricity,  page  23. 
Plaster-casts,  facility  of  obtaining,  \  34. 

 wax  moulds  from,  $  35. 

 diaphragms,  moulds  for,  \  49. 

 of  Paris,  manipulation  with,  \  40. 

 moulds,  §  40. 

7* 


78  INDEX. 

Plaster  of  Paris,  to  be  used  fresh,  \  49. 

 removed  from  wax,  \  36. 

Platinized  silver,  §  65. 
Platinum  terminal  wires,  $  13. 

Pliable  copper,  directions  for  the  production  of,  \\  58,  77. 
Positive  end  of  the  battery,  which  is  the,  §  8. 
Plumbago,  adulteration  of,  \  38. 

 for  wax  moulds,  \  38. 

 mode  of  application  to  wax,  \  39. 

Removing  medals  from  moulds,  \  82. 

Saucers  for  fusible  moulds,  §  25. 

Seals,  mode  of  copying,  \  55. 

Series  of  moulds,  deposition  on  a,  \\  60,  63. 

Silver  for  a  conducting  surface,  §  39. 

Silvery  surface,  production  of,  \  83. 

Single  cell  apparatus,  \  51. 

Smee's  battery,  §  65. 

Soldering,  \  55. 

Solutions,  \  57. 

Stearine  for  moulds,  \  33. 

Tallow,  use  of,  for  saturating  plaster  of  Paris,  \  40. 
Temperature  of  apparatus,  §  58. 
Theory  of  deposits,  general  observations  on  the,  \  81. 
Time  to  produce  electrotype  copies,  \  58. 
Troughs  for  a  series  of  moulds,  g  63. 

Varnish  for  fusible  moulds,  \  31. 
Voltaic  apparatus  for  electrotype,  page  39. 
Voltaic  current,  direction  of  the,  illustrated,  \  9. 
Voltaic  current,  great  effects  of,  $  10. 
 illustrated,  §  4. 


INDEX. 


Water  battery,  page  24. 

Water,  chemical  composition  of\  $  4. 

Wax  moulds,  |  32. 

 cautions  concerning,  $  76. 

 removing  from  medals,  |  32. 

 rendered  conductible,  \  37. 

 used  for  copying  larger  medals,  $  21. 

Wire,  attaching  to  fusible  moulds,  §  31. 

 wax  moulds,  \  39. 

Wood  for  porous  diaphragms,  \  53. 

Zinc  and  copper,  a  voltaic  pair  of,  $  3. 

 mode  of  amalgamating,  $  46. 

Zinc,  pure,  \  46. 


END  OF  PART  I. 


ELECTROTYPE  MANIPULATION. 
PART  II. 


ELECTROTYPE  MANIPULATION! 


PART  II. 

CONTAINING 

THE  THEORY  AND  PLAIN  INSTRUCTIONS 

IN  THE  ARTS  OF 

ELECTRO-PLATING, ELECTRO-GILDING,  AND  ELECTRO-ETCHING; 

WITH  AN  ACCOUNT  OF 

THE  MODE  OF  DEPOSITING  METALLIC  OXIDES, 

AND  OF  THE  SEVERAL 

APPLICATIONS  OF  ELECTROTYPE  IN  THE  ARTS. 
BY 

CHARLES  V.  WALKER, 

Honorary  Secretary  to  the  London  Electrical  Society ;  Editor  of  the  Electrical 
Magazine,  Kaemtz's  Meteorology,  etc.  etc. 
Telegraph  Engineer,  and  Superintendent  to  the  South-Eastern 
Railway  Company. 

ILLUSTRATED  BY  WOOD-CUTS. 
FROM  THE  TWENTY-FIFTH  ENGLISH  EDITION. 

PHILADELPHIA: 
HENRY   CAREY  BAIRD, 

SUCCESSOR  TO  E.  L.  CAREY. 

1852. 


PHILADELPHIA: 
T.  K.  AND  P.  G.  COLLINS,  PRINTERS. 


CONTENTS. 


I.— INTRODUCTORY  OBSERVATIONS. 

PAGE 


Cyanide  of  Potassium       .  .  .  .  .12 

Silver  Solution      .  .  .  .  »  .14 

Oxide  of  Silver      .  .  .  „  .  .14 

Cyanide  of  Silver  .  .  »  .  .  .16 

Preparation  of  the  Gold  Solution  .  .  .  .16 

Single  Cell  for  Plating  and  Gilding  .  .  .17 

Plating  by  means  of  a  Single  Cell  .  .  .20 

Gilding  by  means  of  a  Single  Cell  .  .  .22 

Battery  Process  for  Plating  and  Gilding    .  .  .23 

Voltaic  Condenser  .  .  .  .  .24 

Application  of  Heat  .  fc  .  .  .26 

Preparing  Surfaces  to  unite  with  Gold  and  Silver  .  28 

Cleansing  by  the  Dry  Method        .  .  .  .29 

Cleansing  by  the  Wet  Method       .  .  .  .29 

Amalgamation  to  promote  Adhesion  .  ..  .  32 

Cleaning  Electro-Plate      .  .  .  .  .34 

Gilding-Wax         .  .  .  >  .  .34 

Various  Metallic  Solutions  .  .  .  .35 

Silvering-Liquor    .  .  ,  ,  .  .38 

Gilding-Liqnor       .  .  .  »  .  .38 

Coppering-Liquor  .  „  .  .  .  .39 

Other  Applications  of  Electro-Gilding  .  .  .40 

Daguerreotype  Plates        .  .  .  .  .41 

8 


CONTENTS. 


PAGE 

Electro-Zincing      .          .          .          .  .  .42 

Reduction  of  Alloys         .          .          .  .  .42 

Electro-Tinning     .           .           .           .  .  .43 

Electro-Brass        .           .           .           .  .  .43 

Electrolysis  of  Fused  Compounds            .  .  .44 

Magneto-Electro  Machine           -  .  \        '  .  .  .45 

II.— DEPOSITION  OF  THE  OXIDES  OF  METALS  ON 
METALS.  .    .""    '  ' 

Metallo-Chromes    . .         ..         ..  /  .  47 

Deposition  of  Oxide  of  Lead         .  .       ...  .  .  49 

Deposition  of  Oxide  .of  Iron-                    .  50 

.      III. — ELECTRO-ETCHING. '  , 

Process  of  Electro-Etching        ;■>.:.         .  .  .  52 

Electro-Etching  Daguerreotype  .Plates      .'  .  .  53 

Nature  of  Daguerreotype  Pictures  .         .  .  .54 

M.  Fizeau's  Process.         .,  .  .58 

New  -Mode  of  Etching <      .....  .  .  59 

,  IV. — APPLICATIONS  OF  ELECTROTYPE,  &o. 

Patents      .  -         . .         . .        . .        .  .  .60 

Electro-Tint;  or,  Galvanography  .          .  .  .65 

Glyphography       .  ■         .' .         .          .  -  .  .66 

Metallic  Cloth      ...         .          .          . .  .  .67 

Purity  of  Sulphuric  .Acid  .          .          .  .  .67 

Test  for  Nitric  in  Sulphuric  Acid  .          .  .  .68 

Copying  Busts,  &c."  •         -  •         .  •         .  .  *  69 


■ 


ELECTROTYPE  MANIPULATION. 

PART  II. 


I.— INTRODUCTORY  OBSERVATIONS. 

92.  Having  in  Part  I.  given  the  mode  of  working 
in  copper,  we  pass  on  now  to  other  metals.  First  in  im- 
portance come  gold  and  silver.  The  earliest  experiments 
in  electro-gilding  were  those  by  Brugnatelli,  who  gilded 
silver  medals  by  electricity,  in  1805 ;  he  used  a  solution 
of  nitro-muriate  of  gold  mixed  with  a  solution  of  ammo- 
nia. The  next  were  those  of  De  la  Rive,  in  1841,  who 
used  a  solution  of  chloride  ,  of  gold.  But  these  pro- 
cesses were  interesting  rather  in  a  theoretical  than  in  a 
practical  point  of  view ;  inasmuch  as  the  elective  chemi- 
cal affinity  of  the  elements  (combined  in  these  solutions 
with  the  gold)  for  the  baser  metals,  which  might  be  im- 
mersed in  the  solutions,  is  such,  that  a  violent  inter- 
change of  elements  takes  place,  and  the  gold  is  set  free 
without  even  electric  agency;  and  the  solutions  are 
so  readily  decomposed  by  the  smallest  adventitious  aid, 
that  it  is  a  practical  impossibility  to  obtain  a  "reguline" 


8, 


ELECTROTYPE  MANIPULATION. 


deposit,  however  much  the  voltaic  power  may  be  modi- 
lied. 

The  following  are  illustrations  of  the  deposition  of 
gold  and  silver  by  the  mere  elective  affinity  of  ordinary 
chemical  action  :  If  an  aqueous  solution  of  chloride  of 
gold  is  agitated  with  ether,  the  chloride  leaves  the  water 
to  combine  with  the  ether,  and  the  resulting  compound, 
being  lighter  than  water,  floats  on  the  surface. — If  pieces 
of  polished  steel  are  dipped  into  this  preparation,  they 
acquire  a  coat  of  gold  by  ordinary  chemical  interchange. 
— If  a  design  is  traced  with  solution  of  chloride  of  gold 
upon  a  silk  or  linen  fabric,  and  the  fabric,  while  the 
traces  are  still  moist,  be  exposed  to  a  stream  of  hydro- 
gen gas  (which  may  readily  be  obtained  by  acting  upon 
iron  nails  by  diluted  sulphuric  acid),  the  metal  is  re- 
duced, and  a  golden  design  is  the  result. — If  a  plaster- 
cast  is  saturated  with  a  solution  of  nitrate  of  silver,  and 
placed  under  a  bell-glass,  and  we  admit  to  it  the  gas  pro- 
duced by  heating  a  few  grains  of  phosphorus  with  alco- 
hol and  a  small  quantity  of  potash,  the  silver  will  be 
reduced  upon  the  surface. — If  the  plaster-cast  is  made 
with  sour  whey  instead  of  water,  and  is  saturated  with 
silver  solution,  the  silver  is  reduced  by  mere  exposure  to 
sunlight,  and  forms,  according  to  Elsren,  a  good  conduct- 
ing surface,  in  which  we  can  deposit  copper  or  silver 
according  to  the  usual  modes. 

The  same  observations  apply  to  the  ordinary  salts  of 
silver,  as,  for  example,  the  nitrate,  &c.  In  fact,  long 
before  the  theory  of  chemical  deposits  was  understood, 
I  made  some  experiments  upon  the  electrolysis  of  this 


INTRODUCTORY  OBSERVATIONS. 


9 


salt,  ancl  succeeded  in  producing  an  electrotype  medal 
with  a  silver  surface,  being  I  think  the  first  instance  of 
electro-plating,  when  the  object  of  the  experiment  vjas 
electro-plating.  But  I  was  unsuccessful  in  my  attempts 
to  repeat  the  experiments ;  and  simply  because,  in  that  in- 
stance, I  chanced  to  have  in  action  a  power  nicely  bal- 
anced with  the  work  to  be  performed,  but  in  future 
instances  my  power  was  not  adjusted  to  the  work. 

93.  The  first  practical  process  for  working  in  these 
noble  metals  is  undoubtedly  due  to  the  patentees, 
Messrs.  Elkington.  Others  have  laid  claim  to  having 
been  the  first  to  use  solutions  similar  to  theirs ;  but 
whatever  may  have  been  done  by  these  others  in  private, 
it  does  not  appear  that  the  public  were  in  possession  of 
their  processes  by  any  authentic  publication  ;  and  there- 
fore there  is  no  alternative  but  to  give  the  patentees 
the  claim  of  originality  and  priority. 

94.  The  solutions  they  employ  are  the  argento- 
cyanide  and  the  auro-cyanicle  of  potassium ;  upon 
which  compounds  it  will  be  well  if  we  make  a  few  ob- 
servations here,  at  the  outset.  They  are  what  the 
chemists  term  double  salts:  as,  for  instance,  cyanide 
of  potassium  is  a  compound  simply  of  potassium  and 
cyanogen ;  argento-cyanide  of  potassium  is  silver  and 
cyanogen  combined  with  potassium  and  cyanogen,  or, 
which  amounts  to  the  same  thing,  cyanide  of  silver 
united  with  cyanide  of  potassium. 

When  viewing  (§  13)  what  happened  during  the 
decomposition  of  sulphate  of  copper,  we  had  occasion 
to  describe  that  body  as  oxide  of  copper,  dissolved  in, 

8* 


10 


ELECTROTYPE  MANIPULATION. 


or  combined  with  stdphuric  acid:  now,  oxide  of  copper 
is  1  part  copper  +  1  part  oxygen,  and  sulphuric  acid 
is  1  part  sulphur  +  3  parts  oxygen,  and  a  certain 
quantity  of  water;  so  that,  altogether,  the  arrangement 
is  somewhat  complex.  This  is  not  so  much  the  case 
with  the  bodies  now  in  question.  And  first,  in  respect 
to  the  simple  cyanide  of  potassium,  before  it  is  united 
with  the  gold  or  silver.  It  consists  simply  of  one 
equivalent  of  the  metal  potassium,  and  one  equivalent 
of  cyanogen )  and,  when  it  is  acted  upon  by  a  voltaic 
current  in  the  usual  way,  it  appears  to  be  decomposed 
by  direct  action,  and  cyanogen  is  liberated  at  the  one 
pole,  and  potassium  is  determined  to  the  other,  but  not 
liberated.  It  will  be  remembered  (§  13)  that,  in  the 
solution  of  sulphate  of  copper,  water  was  decomposed  by 
the  direct  action,  and  that  the  copper  was  liberated  by 
a  secondary  action,  namely,  by  the  hydrogen  of  the 
water  returning  back  into  solution  in  the  place  of  the 
copper.  Well;  the  cyanide  of  potassium  is  decomposed 
by  direct  action,  and  potassium  is  presented  to  the 
negative  metal ;  but  a  secondary  action  now  occurs  :  so 
great  is  the  affinity  of  potassium  for  oxygen,  that  it 
cannot  exist  in  a  metallic  form  in  presence  of  that 
element;  as  is  well  known  from  the  common  experiment 
of  dropping  a  piece  of  potassium  upon  water,  when  it 
combines  so  violently  with  the  oxygen  as  to  produce 
heat  and  light;  and  the  resulting  products  are  oxide  of 
potassium,  the  common  cattstic  potash,  accompanied 
with  a  liberation  of  hydrogen.  So,  also,  in  the  present 
case ;  the  potassium  does  not  itself  appear,  but,  in  its 


SOLUTIONS. 


1  1 


place,  we  find  hydrogen  and  potash;  it  takes  oxygen 
from  the  water  and  forms  potash,  and  sets  the  hydrogen 
free.  It  is  true,  we  are  in  possession  of  a  means  of 
preventing  its  return  into  solution,  and  this  is  by  em- 
ploying a  mass  of  mercury  to  receive  it :  in  which  case 
it  unites  with  the  mercury  and  forms  the  amalgam  of 
potassium  ;  and  neither  hydrogen  nor  potash  is  mani- 
fested ;  but  it  will  remain  thus  only  under  favorable 
circumstances ;  for,  if  the  connections  with  the  battery 
are  broken,  so  that  the  mercury  ceases  to  be  negatively 
electrified,  the  potassium  immediately  leaves  it,  and 
decomposes  the  water  as  before.  Thus  much  in  refer- 
ence to  the  simple  cyanide  of  potassium.  Of  the  double 
cyanides,  the  argento  may  be  taken  as  an  example.  It 
consists  of  1  part  cyanide  of  potassium  and  1  part 
cyanide  of  silver — the  latter  cyanide,  like  the  former, 
consisting  of  1  part  metal  +  1  cyanogen.  When  a 
solution  of  this  double  cyanide  is  electrolyzed,  silver 
appears  at  one  pole,  and  cyanogen  at  the  other.  But, 
in  order  to  the  production  of  this  result,  it  is  absolutely 
essential  that  there  be  a  considerable  surplus  quantity  of 
the  cyanide  of  potassium  in  solution ;  indeed,  it  is  pretty 
evident  that  the  direct  action  is  the  decomposition  of 
the  surplus  cyanide,  and  that  the  silver  is  reduced  by 
secondary  action  in  the  following  way.  When  the 
metal  potassium  is  reduced  from  its  cyanide,  it  returns 
into  solution,  and  takes  the  place  of  the  silver  in  the 
double  salt,  setting  the  latter  metal  free ;  so  that, 
while  on  the  one  hand  an  equivalent  of  simple  cyanide 
is  consumed,  on  the  other  hand  an  equivalent  is  formed, 


12  ELECTROTYPE  MANIPULATION. 

and  the  equivalent  previously  engaged  to  form  with 
the  silver  the  double  salt,  is  also  free;  and  thus  far 
there  is  an  increase  in  the  quantity  of  simple  cyanide 
of  potassium.  But,  if  the  positive  metal  is  silver,  the 
cyanogen  combines  with  it  and  forms  cyanide  of  silver; 
for  cyanogen  is  a  gas,  and  like  oxygen  seems  to  combine 
with  metals  in  this  its  nascent  state ;  though,  unlike 
oxygen,  it  is  a  compound  body,  consisting  of  2  equi- 
valents of  carbon  +  1  of  nitrogen,  whence  it  is  also 
termed  bicarb uret  of  nitrogen.  Well ;  cyanide  of 
silver  is  insoluble  in  water,  and  hence  would  form  an 
insulating  crust  on  the  silver  plate  were  it  not  for  the 
presence  of  cyanide  of  potassium  in  excess  in  solution ; 
it  readily  dissolves  in  this,  and  so  keeps  up  the 
strength  of  the  solution ;  and  the  extra  element  of 
cyanide  of  potassium,  mentioned  above,  is  thus  neu- 
tralized. 

Having  thus  described  the  general  character  of  the 
cyanide  solution,  it  remains  for  us  to  give  the  processes 
by  which  the  several  elements  are  most  favorably 
brought  together. 

95.  Cyanide  of  Potassium. — To  obtain  this,  we  set 
out  with  the  ferro-cyanuret  of  potassium,  or  yellow  prus- 
siate  of  potash  of  commerce ;  and  as  this  prussiate  is 
readily  accessible  at  all  chemists',  it  is  better  in  general 
to  purchase  than  to  make  it;  the  mode  by  which  it  is 
obtained  will  be  found  in  any  treatise  on  chemistry.  It 
consists  of  1  equivalent  of  cyanide  of  iron  +  2  equiva- 
lents of  cyanide  of  potassium.  It  is  of  a  bright  yellow 
color,  and  is  converted  into  the  colorless  simple  cyanuret 


SOLUTIONS. 


ie 


in  the  following  manner :  Take  4  oz.  of  the  yellow 
prussiate,  break  it  in  small  pieces,  and  dry  it  well  on  a 
plate  of  iron ;  then  reduce  it  in  a  mortar  to  exceedingly 
fine  powder.  Dry  and  pound  in  like  manner  1J  oz.  of 
carbonate  of  potash.  Incorporate  the  two  ingredients 
thoroughly.  Place  a  Hessian  crucible  in  the  fire;  and 
when  it  attains  a  red  heat,  throw  into  it  the  prepared 
mixture,  and  closely  cover  the  crucible.  Keep  up  the 
heat,  and  the  contents  of  the  crucible  will  soon  fuse,  and 
the  fluid  mass  will  become  redhot.  After  this,  immerse 
in  it,  from  time  to  time,  a  hot  glass  rod;  the  mass  that 
adheres  to  the  rod  in  the  early  stages  of  the  process  is 
brown  on  cooling ;  as  the  heat  is  continued,  it  appears 
yellowish,  and  finally  colorless  and  transparent.  The 
operation  is  then  complete;  the  crucible  must  be  remov- 
ed ;  and  after  its  contents  have  been  allowed  to  settle  the 
fused  mass  may  be  poured  off:  the  greater  portion  of 
which  consists  of  the  simple  cyanuret  of  potassium* 
The  impurities  contained  in  this  product  are  not  detri- 
mental to  its  use,  in  a  general  way,  for  the  purposes  in 
view;  however,  in  cases  where  it  is  required  pure,  it 
must  be  boiled  in  strong  alcohol ;  and  when  the  alcohol 
cools,  the  pure  cyanide  will  be  deposited  in  the  form  of 
small  white  crystals.  This  salt  is  very  deliquescent, 
and  must  therefore  be  retained  in  close  bottles;  it  will 
readily  be  recognized  by  its  powerful  odor — similar  to 


*  This  method  was  first  described  by  Messrs.  Rodgers,  in 
the  Philosophical  Magazine  for  Feb.  1834 ;  and  since  by  Prof. 
Liebig. 


14 


ELECTROTYPE  MANIPULATION. 


that  produced  by  peach-blossoms.  The  mere  mention 
of  prussic  acid  almost  entering  into  its  composition  will 
be  sufficient  to  induce  my  readers  to  exercise  common 
caution  in  handling  it. — A  solvent  solution  is  prepared 
by  adding  two  ounces  of  this  salt  to  a  pint  of  rain  or 
of  distilled  water ;  when  the  salt  is  well  dissolved,  the 
liquid  is  feidy  for  use. 

96.  Silver  Solution. — Silver  may  be  presented  to  the 
above  solution  in  various  forms ;  as  the  oxide,  the  chlo- 
ride, the  carbonate,  the  nitrate,  &c. ;  solution  will  in 
either  case  occur;  and  the  double  cyanide  of  silver  and 
potassium  will  be  produced.  But  since  the  silver,  as 
we  hinted  before,  must  become  a  cyanide  of  silver  before 
it  can  thus  unite  with  the  cyanide  of  potassium,  it  is  ob- 
vious that  one  portion  of  the  solution  must  give  up  its 
cyanogen  to  the  silver,  and  take  to  itself  the  bodies  pre- 
viously in  combination  with  that  metal.  So  that,  from 
the  oxide  of  silver,  potash  would  occur  in  the  solution  ; 
from  chloride,  chloride  of  potassa;  from  carbonate,  car- 
bonate of  potassa ;  and  from  nitrate,  saltpetre.  Of  these 
the  least  likely  to  interfere  with  this  general  action  is 
the  potash ;  and  hence  oxide  of  silver  has  been  frequently 
used.    It  is  thus  prepared : — 

97.  Oxide  of  Silver. — Place  pieces  of  silver  in  a 
glass  vessel,  and  pour  on  them  about  equal  parts  of 
water  and  strong  nitric  acid ;  the  metal  will  soon  dis- 
solve, giving  off  fumes  of  nitric  oxide.  Should  the 
solution  have  a  green  lw|e,  which  is  invariably  the  case 
unless  the  metal  has  bedpu  obtained  fine  from  the  refin- 
ers, it  indicates  the  presence  of  copper ;  in  which  case 


SOLUTIONS. 


15 


immerse  some  pieces  of  copper  in  the  solution,  and  the 
nitric  acid,  by  elective  affinity,  will  combine  with  the 
copper  ;  and  a  precipitate  of  pure  silver,  in  the  form  of  a 
grayish  powder,  will  take  place.  Throw  away  the  liquid, 
and  wash  the  silver  precipitate  several  times  in  sulphuric 
acid  and  water,  and  afterwards  in  water  alone.  Then 
redissolve  it,  as  before,  in  nitric  acid  and  water ;  and  a 
solution  of  pure  nitrate  of  silver  will  be  obtained.  Place 
this  in  an  evaporating  dish,  or  a  saucer,  and  apply  the 
heat  of  a  spirit-lamp,  or  place  the  saucer  by  the  fire- 
side, till  some  portion  of  the  liquid  is  driven  off  in 
vapor.  Allow  the  residue  to  cool,  and  it  will  shoot 
out  into  long,  colorless,  transparent  crystals,  which  are 
nitrate  of  silver.  They  must  be  handled  with  care,  as 
they  possess  the  property  of  staining  animal  and  vege- 
table substances  with  an  almost  indelible  black ;  fused 
nitrate  of  silver  being  the  lunar  caustic  of  surgery, 
and  the  main  ingredient  also  of  marking-ink. — -Next 
prepare  some  lime-water by  stirring  lime  into  water, 
and  filtering  the.  solution.  As  lime  is  very  sparingly 
soluble  in  water,  requiring  at  60°  Fahrenheit  750 
times  its  weight,  it  is  necessary  to  make  an  abundant 
supply.  Place  the  lime-water  in  a  glass  or  other  vessel, 
and  drop  in  it  a  few  crystals  of  nitrate  of  silver  :  the 
colorless  solution  will  instantly  assume  an  unsightly 
brown  hue ;  and,  after  remaining  quiescent  for  a  time, 
the  oxide  of  silver  will  subside  in  the  form  of  a  dark 
brown  precipitate.  The  liquid  is  then  poured  off,  and 
the  precipitate  is  washed  with  water.  Before  throwing 
away  the  liquid,  fresh  lime-water  should  be  added  to  it ) 


16 


ELECTROTYPE  MANIPULATION. 


and  if  the  dark  hue  recurs,  the  precipitate  must  be 
allowed  to  subside  again  :  if  no  change  takes  place,  it 
may  be  inferred  that  the  silver  is  all  extracted.  The 
oxide  of  silver  should  not  be  dried,  but  be  kept  in  bot- 
tles with  water.  A  quarter  of  an  ounce  of  oxide  of 
silver,  added  to  a  pint  of  the  solvent  solution,  forms  a 
very  useful  plating  solution. 

98.  Cyanide  of  Silver. — But,  as  the  above  solution 
is  impure,  in  that  it  contains  as  much  potash  as  is  equiv- 
alent to  the  oxide  of  silver  added,  it  may  not  be  appli- 
cable to  accurate  experiments  ;  and  as  the  potash  is  pro- 
duced, in  the  formation  of  cyanide  of  silver,  at  the  ex- 
pense of  a  certain  portion  of  the  cyanide  of  potassium, 
it  is  a  wise  plan,  for  it  is  no  more  costly,  to  form  the 
cyanide  of  silver  in  a  separate  vessel,  and  to  wash  away 
the  impurities  before  adding  it  to  the  solvent.  Take 
then  a  neutral  solution  of  nitrate  of  silver;  add  care- 
fully a  solution  of  cyanide  of  potassium,  when  a  white 
precipitate  of  cyanide  of  silver  will  fall;  continue 
adding  until  precipitation  ceases.  The  liquid,  which  is 
a  solution  of  nitrate  of  potash  or  saltpetre,  is  to  be 
poured  off,  and  the  precipitate  well  washed.  It  will  be 
pure  cyanide  of  silver,  if  the  materials  employed 
were  pure ;  and  it  is  now  fit  to  be  added  to  the  solvent 
liquid,  to  form  a  plating  solution  free  from  impurities. 

99.  Preparation  of  the  Gold  Solution. — Warm  a 
pint  of  pure  rain  or  distilled  water,  and  dissolve  in  it 
two  ounces  of  cyanide  of  potassium  as  before  ;  then  add 
a  quarter  of  an  ounce  of  oxide  of  gold.  The  solution 
will  at  first  be  yellowish,  but  will  soon  subside  to  color- 


SOLUTIONS  AND  APPARATUS. 


17 


less  transparency.  Those  not  versed  in  chemical  ma- 
nipulation will  be  wiser  to  purchase  than  to  prepare 
oxide  of  gold )  but,  for  general  information,  I  give  the 
process  :  Dissolve  pure  gold  in  two  measures  of  muri- 
atic with  one  of  nitric  acid  5  evaporate  to  dryness ;  dis- 
solve the  residuum  in  twelve  times  its  weight  of  water ; 
add  to  this  a  solution  of  pure  carbonate  of  potash,  dis- 
solved in  twice  its  weight  of  water ;  apply  a  moderate 
heat,  about  170°,  and  a  reddish-yellow  precipitate  oc- 
curs. This  is  the  hydrated  peroxide  of  gold.  Wash 
it  well ;  and,  to  render  it  anhydrous,  boil  it  in  water. 
It  then  assumes  a  brownish-black  color,  which  is  the 
oxide  required. 

100.  I  by  no  means  give  these  as  standard  propor- 
tions of  the  several  ingredients  required.  They  are  the 
proportions  which  I  employed  with  success  in  gilding 
and  plating  the  series  of  metals  (submitted  to  the 
Electrical  Society  at  their  meeting,  Sept.  21,  1841), 
by  the  battery  process  to  be  hereafter  described.  When 
the  same  object  is  effected  by  the  employment  of  a  sin- 
gle cell,  it  will  be  requisite  to  alter  the  degree  of 
saturation  according  to  circumstances ;  to  which,  how- 
ever, I  shall  have  further  to  allude  in  the  sequel. 

101.  Single  Cell  for  Plating  and  Gilding.  —  The 
necessity  of  economizing  solutions  of  such  value  as 
these  has  led  to  certain  modifications  in  the  apparatus 
contributing  to  that  end.  The  porous  cell  (§  17), 
which  in  other  arrangements  contains  the  zinc  and  acid, 
and  is  surrounded  by  the  copper  or  other  negative  ele- 
ment, in  the  present  process  contains  the  cyanide  solution% 

9 


18 


ELECTROTYPE  MANIPULATION. 


and  the  negative  element  or  object  to  receive  the 
deposit,  and  is  surrounded  by  the  zinc,  &c. 

102.  This  arrangement  will  be 
Fig.  11.          readily  understood  by  a  glance  at  the 

annexed  wood-cut,  which  represents  a 
porcelain  cell  containing  a  cylinder  of 
zinc,  and  an  inner  porous  tube  filled 
with  the  solution  of  silver  or  gold. 
Connection  is  made  between  the  zinc 
and  medal  or  mould  by  a  binding 
screw;  or  by  a  mere  contact,  as  in 
the  figure. 

103.  I  must  again  dwell  upon  the 
philosophy  of  the  action  of  this  ar- 
rangement, and  return  to  first  princi- 
ples, in  order  to  impress  them  more  firmly  on  the  minds 
of  those  who  read  these  pages  with  the  intent  to  repeat 
the  experiments.  For  it  is  a  matter  of  some  importance, 
in  employing  the  costly  salts  of  the  noble  metals,  to  have 
the  principles  of  the  experiment  traced  out  as  distinctly 
as  possible. 

104.  In  the  arrangement  just  described,  the  nature 
of  the  deposit  will  depend  upon  the  principles  elsewhere 
(§  78)  set  forth;  and,  d  fortiori,  from  the  facility  with 
which  the  salts  of  silver  or  gold  are  decomposed,  there 
will  be  a  much  greater  chance  of  releasing  hydrogen, 
and  spoiling  the  experiment;  to  prevent  which,  there- 
fore, ample  provision  must  be  made.  For  instance,  if 
the  silver  solution  is  weak  in  proportion  to  the  energy 
of  action  between  the  zinc  and  acid  water,  the  electricity 


SOLUTIONS  AND  APPARATUS. 


19 


developed  will  be  more  than  sufficient  to  release  pure 
metal,  and  hydrogen  will  be  evolved,  the  result  being  a 
deposition  of  oxide.  Or,  if  the  balance  between  the 
strength  of  the  solutions  be  duly  adjusted,  the  relation 
between  the  size  of  the  zinc  and  of  the  medal  or  mould 
may  be  such  as  to  determine  the  same  result.  It  is 
therefore  requisite  that  the  water  which  excites  the  zinc 
should  contain  very  little  acid — a  few  drops,  more  or 
less  in  proportion  as  the  cyanide  solution  contains  more 
or  less  of  the  oxide;  and  that  the  strength  of  the  latter 
should  be  maintained  by  a  fresh  supply  of  oxide  from 
time  to  time. 

105.  Another,  and  in  some  cases  more  convenient 
form  for  the  single-cell  apparatus  is  given  in  the  annexed 

Fig.  12. 


wood-cut ;  in  principle  it  differs  nothing  from  the  former ; 
the  porous  cell  to  contain  the  cyanide  solution  being  flat, 
affords  the  means  of  immersing  a  larger  medal,  without 
an  extravagant  supply  of  liquid.    The  zinc  which  en- 


20 


ELECTROTYPE  MANIPULATION. 


velops  the  porous  cell  is  also  flat.  The  connections  are 
made  as  before. 

106.  Plating  by  means  of  a  single  Cell. — Having 
charged  either  of  these  arrangements  with  the  weak  acid 
water  and  the  solution  of  silver,  let  it  remain  for  a  few 
minutes,  in  order  that  the  porous  cell  may  be  moistened 
through,  and  that  action  may  commence  as  soon  as  the 
circuit  is  completed.  Then  attach  a  thin*  pliable  wire 
to  the  medal  or  mould,  and  place  its  other  end  in  con- 
tact with  the  wire  attached  to  the  zinc :  complete  the 
circuit  by  immersing  the  metal  in  the  silver  solution, 
and  a  deposition  will  instantly  take  place.  It  will  pre- 
sent a  dead  whitish  appearance.  At  the  meeting  of  the 
British  Association  in  Birmingham,  in  1849,  Mr.  Elk- 
ington  stated,  "that  a  few  drops  of  the  sulphuret  of 
carbon,  added  to  the  cyanide  of  silver  in  the  decompos- 
ing cell,  had  the  property  of  precipitating  the  silver 
perfectly  bright,  instead  of  being  granulated  so  dead  as 
it  is  when  thrown  down  from  the  solutions  ordinarily 
employed." 

107.  Should  the  silver  deposit  present  a  whitish  sur- 
face, streaked  with  perpendicular  black  lines,  it  may  be 
regarded  as  an  indication  that  the  action  is  attended 
with  a  development  of  hydrogen:  this  must  be  pre- 

*  This  principle,  so  often  alluded  to,  of  retarding  or  restrain- 
ing the  energy  of  the  action,  is  regarded  in  the  employment  of 
thinvrire;  it  is  a  very  valuable  adjunct  to  the  other  means  (§  78) 
of  obtaining  the  same  end;  and  may  often  be  adopted  with 
advantage. 


SOLUTIONS  AND  APPARATUS. 


21 


vented  by  some  of  the  means  so  often  mentioned  (§  78, 
&c.).  By  careful  attention  at  the  commencement  of  the 
process  the  right  degree  of  action  is  readily  obtained; 
and  if  the  process  is  continued  (with  occasional  watch- 
ing) for  about  half  an  hour,  the  medal  will  be  beautifully 
coated  with  dead  silver.  In  that  condition  it  may  re- 
main, after  being  washed,  and  dried  in  blotting-paper. 
Or,  if  a  burnish  is  desired,  the  leather  and  plate  brush 
must  be  used ;  or  it  may  be  thrown  down  bright  as 
above  (§  106). 

Mr.  Bain  has  patented  an  instrument  which  he  styles 
a  "  Voltaic  Governor."  The  plates  of  the  voltaic  ar- 
rangement are  immersed  to  a  depth  sufficient  to  produce 
the  electricity  required.  They  are  suspended  in  the 
liquid  as  weights  to  a  clock-work  arrangement.  When 
the.  action  diminishes,  a  keeper  from  an  electro-magnet, 
through  which  the  current  passes,  is  moved,  and  the 
plates  are  said  to  sink  until  enough  of  electricity  is 
generated  to  cause  the  electro-magnet  again  to  attract 
the  keeper.* 

If,  instead  of  plating  medals,  the  object  is  to  deposit 
silver  in  a  mould,  as  mentioned  elsewhere,  the  same 
preparations  are  to  be  made ;  but  the  mould  should  be 
allowed  to  remain  for  some  minutes  (more  or  less  ac- 
cording to  the  thickness  required)  subject  to  the  action 
of  the  current.  It  may  then  be  removed,  and  after 
being  washed  with  water,  and  afterwards  with  water 
containing  a  few  drops  of  nitric  acid,  may  be  placed 


*  Vide  Mech.  Mag.  5th  Aug.  1843. 
9* 


22 


ELECTROTYPE  MANIPULATION. 


with  proper  connections  in  a  copper  solution  (§  57),  to 
remain  there  till  it  is  sufficiently  backed  up  with  this 
metal. 

108.  Gilding  hy  means  of  a  single  Cell. — The  opera- 
tion of  gilding  is  conducted  much  in  the  same  manner 
as  that  of  plating — gilding,  however,  requiring  a  little 
longer  time,  and  occasionally  hot  solutions. 

109.  The  operations  of  gilding  and  plating  seem  at 
first  to  have  been  very  generally  effected  by  means  of 
the  single  cell,  in  a  manner  more  or  less  in  accordance 
with  the  directions  I  have  just  given,  as  the  nature  of 
the  case  permitted.  In  fact,  plating  by  this  process 
had  been  adopted  on  a  scale  of  some  magnitude  in  the 
great  manufacturing  town  of  England ;  the  strength 
of  the  solution  being  maintained  by  fresh  supplies  of 
the  oxide  of  either  gold  or  silver.  And  if  attention 
be  paid  to  the  instructions  given,  there  is  little  fear  of 
failing. 

110.  Before  describing  a  method  which  appears  far 
superior  to  this,  I  would  direct  attention  to  the  source 
whence  the  silver  and  gold  in  the  single  cell  process  are 
obtained,  viz.,  from  the  oxides,  for  instance.  For  every 
ounce  of  these  metals  deposited,  a  quantity  of  the  oxide 
must  be  furnished  which  shall  contain  in  it  an  ounce  of 
pure  metal ;  and  hence  for  every  ounce  of  metal,  much 
more  than  an  ounce  of  oxide  is  consumed.  The  time 
and  trouble  required  to  effect  the  combination  between 
these  metals  and  oxygen  are  by  no  means  inconsider- 
able; and  hence  the  expense  of  first  producing  the 
oxide  of  gold  or  silver,  and  then  releasing  either  from 


SOLUTIONS  AND  APPARATUS. 


23 


the  after-combination  with  cyanogen,  far  exceeds  the 
actual  cost  of  the  metal  employed  :  how  far  depends 
upon  circumstances.  The  object,  however,  may  be 
accomplished  with  far  more  certainty,  and  at  consider- 
ably less  expense  by  means  of  an  additional  cell 
(§  56),  and  a  plate  or  wire,  &c.  of  gold  or  silver,  to 
keep  up  the  strength  of  the  solution,  as  in  the 
case  of  sulphate  of  copper.  This  method  is  now 
adopted  generally  by  the  several  patentees  ;  for  experi- 
ments with  solutions  of  silver  and  gold  in  union  with 
cyanogen,  have  shown  that  cyanogen  nascent  at  the 
positive  plate  in  a  decomposition  cell  will  combine 
with  silver  and  also  with  gold.  This  furnishes  a 
means  of  gilding  and  plating,  by  the  use  of  a  generating 
cell  to  furnish  the  electricity,  and  a  decomposition 
cell  to  contain  the  cyanide  solution;  the  nature  of 
the  changes  produced  has  already  (§  95)  been  de- 
scribed. 

111.  Battery  Process  for  Plating  and  Gilding. — 
The  generating  cell  for  acting  upon  solutions  of  silver 
need  not  be  large.  A  pint  Daniell,  similar  to  that 
in  the  wood-cut,  or  a  series  of  two,  is  sufficient  for 
larger  medals  than  can  be  placed  in  the  decomposition 
cell  attached.  The  latter  is  of  porcelain  or  glass.  Of 
course,  the  size  varies  according  to  the  extent  of  the 
experiment.  The  zinc  may  be  used  unamalgamated, 
and  excited  with  salt  and  water;  the  copper  cell  of 
the  Daniell's  battery  contains,  as  usual,  a  solution  of 
the  sulphate  (§  57).  Gilding  may  be  better  accom- 
plished by  using  three  cells  of  Daniell's  battery. 


24 


ELECTROTYPE  MANIPULATION. 


Fig.  13. 


112.  Voltaic  Condenser. — Prof.  De  la  Rive  has 
introduced  an  instrument,  which  he  has  named  the 
Voltaic  Condenser,*  and  which  may  probably  be  of  some 
service  in  electro-gilding  and  plating.  Its  property  is 
to  give  to  one  cell  of  a  battery  the  intensity  of  two  or 
three,  being  the  power  required  for  these  processes; 
and  it  does  this  at  the  expense  of  only  one  equivalent 
of  zinc.  It  is  well  known  to  electricians  that  at  the 
moment  contact  is  made  with  the  battery,  so  as  to  send 
a  voltaic  current  along  a  wire  in  one  direction,  a 
secondary  current,  which  endures  but  for  an  instant,  is 
induced  in  the  wire  in  the  reverse  direction ;  and  when 
contact  is  broken,  so  that  the  original  current  ceases, 
the  secondary  current  is  induced  to  move  in  the  direc- 


*  Vide  Arch  de  V Elect.  No.  8,  p.  173,  and  Elec.  Mag.  p.  38. 


SOLUTIONS  AND  APPARATUS. 


25 


tion  contrary  to  its  original  motion;  and  therefore  in 
the  same  direction  as  that  pursued  by  the  primary 
current,  when  contact  was  first  made.  The  intensity 
of  this  current  greatly  depends  on  the  quantity,  the 
character,  and  the  form  of  the  wire  employed ;  and  if 
the  wire  is  coated  with  silk  and  wound  round  a  bobbin, 
the  intensity  is  greatly  increased.  M.  De  la  Rive  uses 
100  convolutions  of  three  stout  copper  wires,  and 
places  within  the  coil  a  bar  of  soft  iron,  the  use  of 
which  will  soon  become  evident.  The  object  of  the 
arrangement  is  to  convey  the  battery  current,  and  with 
it  the  secondary  current  through  the  solution  to  be 
decomposed. 

113.  For  example,  we  will  select  the  gold  solution 
to  illustrate  the  use  of  the  condenser.  Metallic  connec- 
tions are  applied  between  the  ends  of  the  coil  and  the 
two  terminations  of  a  DanielPs  or  Sniee's  battery.  The 
connections  are  continued  to  a  vessel  containing  the 
gold  solution,  the  arrangement  being  somewhat  like  the 
figure  oo ,  where  the  generating  cell  is  to  the  right,  the 
coil  in  the  centre,  and  the  decomposition  cell  to  the  left. 
The  current,  on  leaving  the  battery,  has  thus  the  choice 
of  two  paths,  the  one  being  through  the  coil,  the  other 
through  the  solution ;  but  from  the  great  comparative 
resistance  of  liquids,  compared  with  metals,  far  the 
larger  portion  would  pass  through  the  coil,  while  a  com- 
paratively small  share  would  traverse  the  solution  of 
gold.  In  passing  through  the  coil,  however,  it  converts 
the  soft  iron  core  into  a  magnet ;  this  magnet  instantly 
attracts  a  piece  of  iron,  which  is  so  arranged  that,  on 


26 


ELECTROTYPE  MANIPULATION. 


being  raised,  it  removes  a  wire  and  thus  breaks  off  com- 
munication between  the  coil  and  the  generating  cell, 
except  by  means  of  the  cell  containing  the  solution. 
The  current  therefore  now  passes  through  the  gold  solu- 
tion. But  when  the  coil  ceased  to  be  alone  in  the  cir- 
cuit, a  secondary  current  was  induced  in  the  same  direc- 
tion as  the  original  battery  current ;  this,  therefore, 
joins  with  the  said  generating  current,  and  both  pass 
together  through  the  gold  solution ;  by  which  means  the 
actual  power  of  the  battery  is  very  greatly  exalted. 
Now,  the  iron  core  loses  most  of  its  magnetism,  as  soon 
as  the  liquid  is  included  in  the  circuit ;  and  hence  the 
piece  of  iron,  the  raising  of  which  broke  contact,  falls 
again,  and  the  coil  is  again  included,  when  the  same 
phenomena  recur ;  and  thus,  by  a  continual  succession 
of  breaking  and  making  contact,  the  current  of  a  mo- 
ment, namely,  the  secondary  current,  is  created,  and 
employed  with  very  great  advantages.  My  readers 
must  be  content  with  this  general  description ;  and  I 
must  trust  to  their  own  ingenuity  for  making  arrange- 
ments agreeable  to  these  directions. 

114.  Application  of  Heat. — Considerable  advantage 
accrues  in  all  cases  of  the  deposition  of  metals  where 
adhesion  is  desired,  by  the  use  of  heat.  It  expands  the 
baser  metal,  and  so  far  opens  its  pores  that  the  subse- 
quent contraction,  consequent  on  the  effect  of  common 
temperatures,  is  likely  to  operate  favorably  in  binding 
the  metals  together.  It  has  other  advantages,  espe- 
cially in  gilding.  The  mode  of  heating  the  solutions 
will  depend  entirely  on  the  circumstances  under  which 


SOLUTIONS  AND  APPARATUS. 


27 


the  experiments  are  conducted.  If  a  hot  stove,  or  a 
sand-bath  be  at  hand,  the  object  is  soon  accomplished ; 
but,  in  most  cases,  a  simple  plan  is  to  use  a  lamp  and  a 
glass  or  other  retort,  and  convey  steam  by  a  glass  tube 
into  the  metallic  solution,  either  of  the  single  cell  appa- 
ratus, or  that  contained  in  the  decomposition  cell. 

115.  With  regard  to  the  time  requisite  for  plating 
and  gilding,  it  is  entirely  dependent  on  the  nature  and 
uses  of  the  article.  The  thickness  of  the  deposit,  of 
course,  depends  on  the  duration  of  the  action.  For 
medals,  and  such  things  as  are  not  exposed  to  wear,  a 
few  minutes'  immersion  may  be  enough;  for  spoons, 
forks,  plated  goods,  &c,  subject  to  much  wear,  six  or 
eight,  or  even  more  hours ;  always  taking  care  to  watch 
the  process  at  times,  in  order  to  prevent  the  occurrence 
of  the  black  lines;  whenever  they  appear,  the  action 
must  be  retarded.  Large  objects,  or  those  which  are 
subject  to  a  long  action,  should  be  occasionally  with- 
drawn, and  their  position  should  be  altered ;  so  that  a 
uniformity  of  deposit  may  occur.  Motion  of  the  arti- 
cles during  the  process  has  been  recommended,  and  with 
some  show  of  reason.  The  readiest  method  of  produc- 
ing it  is  to  suspend  the  article  in  the  solution  from  a 
common  bottle-jack,  and  connect  the  latter  with  the 
battery.  Or,  on  the  large  scale,  when  it  would  not  be 
convenient  to  have  a  roasting-jack  for  each  group  of 
articles,  it  might  be  convenient  to  have  a  constant  flow 
of  the  solution.  The  surface  obtained  in  the  deposition 
of  silver  by  electrolysis  is  technically  termed  "  dead." 
Medals  thus  coated,  if  care  be  exercised  during  the  ope- 


28 


ELECTROTYPE  MANIPULATION . 


ration,  are  very  beautiful,  and  should  be  prepared  for 
the  cabinet  by  simply  washing  in  water.  If  a  bright 
surface  is  desired,  they  are  polished  with  a  leather  and 
plate  powder  (§  107).  Ordinary  plated  goods  are 
finished  off  by  polishing  and  burnishing.  A  steel  or 
agate  burnisher  is  used.  In  articles  of  jewellery  some^ 
parts  are  left  dead,  and  others  are  made  bright. 

116.  Preparing  Surfaces  to  unite  with  Gold  and 
Silver. — But  we  are  going  on  too  fast ;  I  must  return  to 
certain  things  preliminary  to  plating  and  gilding,  which 
I  had  passed  over,  in  order  not  to  interrupt  the  pro- 
gressive illustrations  of  the  nature  and  preparation  of 
the  solutions.  I  allude  to  the  preparation  of  the  sur- 
faces, previous  to  applying  the  metals )  which  is  a  point 
of  such  paramount  importance  that,  unless  duly  regarded, 
all  subsequent  operations  will  be  futile ;  and  it  would  be 
vain  to  hope  for  perfect  adhesion  between  the  metallic 
base  and  the  deposit ;  the  latter  will  rise  up  in  blisters 
where  the  surface  is  not  properly  prepared,  and  can 
easily  be  rubbed  off. 

117.  There  are  two  methods  of  preparing  metals  for 
the  reception  of  other  metals — the  wet  way,  and  the  dry 
way.  The  experiments  of  M.  Becquerel  and  others  are 
decidedly  in  favor  of  the  latter;  but,  as  it  cannot  be 
adopted,  except  in  certain  cases,  where  the  work  of  the 
article  is  plain,  and  the  article  itself  is  not  delicate,  it 
will  be  necessary  to  describe  both  modes.  The  main  in- 
tent of  cleansing  is  that  the  contact  between  the  two 
metals  may  be  perfect ;  and  it  effects  this  by  removing 
grease  and  all  extraneous  matter,  especially  the  oxides, 


CLEANSING  PROCESSES. 


29 


which  are  ever  found  on  the  surface  of  the  less  noble 
metals. 

118.  Cleansing  ly  the  Dry  Method. — The  advantage 
of  the  dry  process  over  any  in  which  moisture  has  been 
employed,  is  that,  in  the  latter  case,  several  seconds,  at 
least,  must  always  pass  between  the  act  of  removing  the 
article  from  its  last  liquid  bath,  and  placing  it  in  the 
solution  of  the  metal  to  be  deposited ;  and  during  this 
short  interval,  the  article,  or  some  portion  of  it,  very 
frequently  undergoes  an  alteration,  trivial,  indeed,  but 
still  an  alteration,  by  the  action  of  the  air,  which  pro- 
duces a  film  of  oxide,  infinitely  thin,  it  is  true,  yet  quite 
enough  to  militate  against  the  success  of  the  experiment, 
as  regards  permanent  adhesion.  Therefore,  wherever 
the  dry  process  can  be  adopted,  it  is  decidedly  the 
better;  although,  from  the  very  nature  of  the  articles 
subjected  to  the  process,  the  number  of  cases  in  which 
it  is  available  is  very  limited.  The  dry  process  is  mere- 
ly the  operation  of  scouring  with  sand,  or  glass,  or  emery- 
paper,  as  the  case  may  be,  or  with  very  fine  powder  of 
pumice-stone;  using  clean  brushes,  utterly  free  from 
grease.  Sometimes  fine  files  may  be  used ;  indeed, 
all  depends  on  the  value  and  character  of  the  article 
operated  upon.  It  must  be  remembered  throughout  that 
grease  and  oxide  are  the  great  enemies  to  be  expelled; 
and  therefore,  especial  care  must  be  taken  to  avoid  con- 
tact with  the  moisture  of  the  hand,  which  is  of  a  nature 
to  produce  either. 

119.  Cleansing  by  the  Wet  Method. — The  solutions 
employed  may  be  divided  generally  into  two  classes,  the 

lb 


30 


ELECTROTYPE  MANIPULATION. 


acid  and  the  alkaline;  the  action  of  the  former  is  directed 
more  towards  the  removal  of  oxides,  &c. :  that  of  the  latter 
to  the  removal  of  grease.  As  a  rule,  I  would  always 
follow  the  use  of  an  acid  bath  by  an  alkaline,  having 
first  washed  away  the  acid  in  several  waters;  and  this 
may  be  done,  whether  the  operation  commence  with  an 
alkaline  bath  or  not.  The  following  are  some  of  the 
modes  in  use;  they  are  all  effectual  according  to  the  cir- 
cumstances which  give  preference  to  one  over  the  other : 
The  method  recommended  by  M.  Boettiger,  in  his  ac- 
count of  gilding,  given  in  the  Annalen  der  Chimie  und 
der  Pharmacie,*  may  be  adopted.  He  says :  "  It  is  very 
necessary  to  rub  the  metal  according  to  circumstances,f 
with  extremely  fine  sand,  moistened  with  hydrochloric 
acid  mixed  with  a  little  chalk,  so  that  there  shall  remain 
no  trace  of  oxide  of  copper. "  Another  effectual  method 
is  immersing  the  article  in  a  mixture  technically  termed 
"  pickle."    This  may  be  made  of 

Sulphuric  acid       .       .       .       .64  parts. 

Water  64  <* 

Nitric  acid  32  " 

Muriatic       .       .       .       .       .1  part. 

The  "  pickle"  is  used  by  tying  a  wire  round  the  article 
and  immersing  it  for  a  second  or  two ;  the  action  is  very 
energetic,  and,  of  course,  is  not  suited  to  the  prepara- 


*  Vol.  xxxv.  p.  350. 

f  /.  e.  when  it  can  be  done  without  injury  to  the  object  of  ex- 
periment ;  and  this,  too,  must  be  the  guide  in  the  application  of 
the  other  modes. 


CLEANSING  PROCESSES. 


31 


tion  of  medals :  for  medals,  the  mixture  should  be  very 
much  diluted,  and  they  should  remain  in  it  for  a  short 
time.  A  mere  bath  of  dilute  nitric  acid  is  often  used. 
Nitric  acid,  mixed  with  sea-salt  and  soot,  is  often  rubbed 
on  the  article.  Concentrated  sulphuric  acid  and  sea- 
salt  is  another  mode. — Of  the  alkaline  solutions  are 
caustic  soda,  or  solution  of  soda  and  ammonia,  or  caustic 
soda  and  sal-ammoniac ;  or  the  articles  maybe  boiled  in 
a  solution  of  common  soda  or  potash,  which  is  a  very 
good  method  of  cleansing  them. 

120.  Whatever  solution  is  used,  whether  acid  or  al- 
kaline, or  the  detergent  paste  of  soot,  or  chalk  and  acid, 
fresh  water  must  not  be  spared  for  rinsing  off  all  remain- 
ing traces;  and  the  article  must  be  dried  for  immediate 
use  by  pouring  over  it  boiling  distilled  or  rain  water; 
or,  if  the  process  of  deposition  is  not  to  be  commenced 
immediately  after  the  rinsing,  it  may  be  buried  in  hot 
or  cold  boxwood  sawdust,  until  required  5  it  may  often 
be  dried  for  immediate  use  in  hot  sawdust.  In  addition 
to  the  detergent  methods  already  given,  an  ancillary 
means,  which  has  been  found  effectual,  depends  upon 
the  fact  that  metallic  and  other  surfaces,  after  exposure 
to  the  air  for  some  hours,  become  coated  with  a  film  of 
air  so  intimately  as  to  retain  it,  even  (as  in  electrotype 
cases)  between  themselves  and  any  metal  deposited  upon 
them.  In  fact,  we  have  been  advised,  in  copying  large 
subjects  by  electrotype,  to  take  advantage  of  this, 
and  to  allow  the  film  to  arrange  itself,  before  the  plate 
is  submitted  to  the  action  of  the  battery.  For  it  is 
found  that  the  presence  of  this  natural  film  very  materi- 


32 


ELECTROTYPE  MANIPULATION. 


ally  operates  in  preventing  adhesion  between  the  plates 
and  the  deposit :  whereas,  in  the  absence  of  the  film, 
unless  its  place  has  been  supplied  by  something  else, 
other  things  being  in  order,  the  two  will  effectually  be- 
come one.  We  are  advised,  too,  after  soldering  a  wire 
to  a  copper  plate,  to  allow  the  latter  to  remain  an  entire 
day,  to  regain  the  film  of  air  which  had  been  driven  off 
by  the  heat.  Carrying  out  this  principle,  the  boiling 
alkaline  solution  and  the  boiling  water  answer  a  double 
end  ;  and  hence  are  very  effectual  means  of  promoting 
perfect  union  between  the  metals.  Heat  operates  still 
more  favorably  in  causing  the  expansion  of  the  metal, 
as  I  mentioned  when  recommending  its  adoption  in  the 
process  itself  of  electric  deposition.  Iron  may  be  pre- 
pared and  cleaned  by  electrolytic  action,  as  described 
elsewhere  (§  166).  In  preparing  steel  for  gilding  it 
must  be  polished  without  oil,  as  the  oily  particles  ad- 
here so  closely  that  it  is  scarcely  attacked  by  strong 
muriatic  acid. — The  last  cleansing  method  I  have  seen, 
and  it  is  a  capital  one,  is  to  scour  the  surface  with  Calais 
sand,  moistened  by  the  silver  or  gold  solution,  and  rub- 
bed in  with  a  scratch-brush. 

121.  Amalgamation  to  promote  Adhesion. — Another 
method  in  this  preparatory  stage  of  the  proceedings,  to 
which  I  shall  allude,  is  that  recommended  by  M.  Bec- 
querel;*  and  which  promises  to  be  of  great  avail  in 
insuring  a  successful  termination  to  the  experiment. 
After  the  articles  are  thoroughly  cleaned,  according  to 


*  Vide  Les  Comptes  Eendus,  July  3,  1843. 


CLEANSING  PROCESSES. 


33 


the  instructions  now  laid  d own ,  they  are  dipped  into  a  solu- 
tion of  proto-nitrate  of  mercury )  when  taken  out  they 
are  washed  in  abundance  of  water ;  and  are  then  rubbed 
with  leather,  in  order  to  promote  the  equal  spread  of 
the  mercury.  These  operations  are  repeated  until  the 
whole  surface  is  well  coated  with  mercury.  The  ultimate 
character  of  the  metallic  deposit  depends  on  the  surface 
given  to  the  mercury  ;  if  the  employment  of  the  leather 
is  only  such  as  is  needed  to  effect  the  more  equal  diffu- 
sion of  the  mercury,  the  surface  is  dull  or  dead,  and  so 
is  the  deposit ;  whereas,  if  brisk  friction  is  applied,  and 
the  mercury  receives  a  good  polish,  such  will  be  the 
character  of  the  metal  thrown  down.  And  thus  may 
burnished  gold  or  dead  gold  be  produced  at  pleasure. 
By  adopting  this  method  of  giving  a  mercurial  coat  as 
the  foundation  for  the  plating  or  gilding  (and  it  is  espe- 
cially valuable  for  the  latter),  a  double  advantage  ac- 
crues ;  the  close  adherence  between  the  metals  is  insured 
— and  a  coating  of  gold  of  any  thickness  may  be  thrown 
down.  The  mercury  is  subsequently  driven  off  by  heat; 
either  heat  applied  for  the  purpose,  or  the  heat  employed 
in  some  of  the  operations  by  which  the  work  is  finished. 

122.  German  silver  is  prepared  by  allowing  it  to 
remain  for  three  or  four  hours  in  a  cold  solution  of  car- 
bonate of  potash.  It  is  then  washed  in  cold  water,  and 
dipped  into  dilute  nitric  acid.  After  again  washing 
and  drying  it,  it  is  rubbed  with  leather ;  and  imme- 
diately before  placing  it  in  the  silver  solution,  it  is 
dipped  into  a  solution  of  common  salt,  containing  a 
little  gum. 

10* 


34 


ELECTROTYPE  MANIPULATION. 


123.  Cleaning  Electro-plate. — Electro-plating,  espe- 
cially of  dead  silver,  is  very  liable  to  turn  yellow,  after 
a  few  days'  exposure  to  the  light.  M.  Mourey  found* 
that  this  was  due  to  the  decomposition  of  a  cyanuret  or 
a  sub-cyanuret  remaining  on  the  silver  surface  on  its 
emersion  from  the  solution.  He  removes  it  in  the  fol- 
lowing manner  :  The  articles  are  covered  with  a  thick 
layer  of  dissolved  borax,  and,  being  placed  in  a  muffle, 
are  submitted  to  a  heat  somewhat  below  cherry-red, 
which  is  sufficient  to  calcine  the  borax.  They  are  then 
thrown  into  water  acidulated  with  sulphuric  acid,  and 
allowed  to  remain.  After  being  withdrawn  from  this, 
they  are  washed  in  water  and  dried,  first  in  hot  sawdust 
and  then  on  a  stove  or  otherwise.  The  result  is  the 
production  of  that  white  color  so  essentially  requisite 
to  dead  silver,  especially  in  articles  of  jewellery.  I 
may  add  to  this  a  process  for  cleaning  tarnished  silver 
in  general,  which,  though  not  much  known  here,  is 
practised  constantly  by  the  natives  in  India.  A  few 
tamarinds  are  placed  in  water  contained  in  an  earthen 
vessel,  and  the  silver  articles  are  boiled  in  it  for  a  time, 
and  they  emerge  clean  and  very  white. 

124.  Gilding-Wax. — The  proper  color  is  given  to 
the  surface  of  electro-gilding  by  covering  it  with 
gilding-wax,  and  heating  it  till  the  mass  begins  to 
smoke.  Gilding-wax  consists  of  the  powders  of  salt- 
petre, sal-ammoniac,  sulphate  of  iron,  and  verdigris, 
mixed  with  melted  wax.    This  operation  removes  the 


*  Vide  Comptes  Renclus,  April  3,  1843,  p.  660. 


SOLUTIONS. 


35 


brassy  appearance,  which  the  surface  often  presents,  and 
gives  the  rich  gold  color,  on  which  the  beauty  of  the 
work  depends. 

125.  Various  Metallic  Solutions. — M.  Louyet  has 
used  with  great  success  a  solution  of  bisulphuret 
of  gold  in  cyanuret  of  potassium.  This  solution  is 
neutral  to  silver,  copper,  and  brass,  so  that  no  action 
occurs  on  the  surface  of  these  metals  until  the  circuit 
is  completed.  The  bisulphuret  of  gold  is  prepared  by 
passing  sulphuretted  hydrogen  through  a  solution  of 
bichloride  of  gold;  or  by  pouring  into  such  solution 
hydro-sulphate  of  ammonia.  The  bisulphuret  is  col- 
lected in  a  filter,  where  it  must  be  well  washed  with 
warm  not  boiling  water :  it  is  then  dissolved  by  pouring 
the  cyanuret  solution  (§  95)  through  the  filter.  The 
solution  has  a  clear  gold  color;  it  is  diluted  for  use  to  a 
pale  straw  color. 

126.  M.  Becquerel  has  introduced  a  very  philoso- 
phical mode  of  gilding  by  the  single  cell  process.  A 
solution  was  made  of  1  gramme  of  dry  chloride  of 
gold,  10  of  ferro-cyanuret  of  potassium,*  and  100 
of  water;  it  was  filtered,  and  to  it  were  added  100 
grammes  of  a  saturated  solution  of  yellow  ferro- 
cyanuret  of  potassium :  The  solution  was  used  in  that 
state,  or  diluted  with  once  or  twice  its  bulk  of  water, 
according  to  the  character  of  surface  desired.  This 
solution  is  placed  in  the  porous  tube  of  a  single  cell 
(§  18),  and  into  the  cell  surrounding  the  zinc  is  poured 


*  The  prussiate  of  potasli  of  commerce. 


36 


ELECTROTYPE  MANIPULATION. 


a  solution  of  a  similar  character,  with  the  exception  that 
it  does  not  contain  any  gold;  but,  in  lieu  thereof,  it 
contains  a  little  common  salt.  Unamalgamated  zinc  is 
used. 

127.  There  is  not  space  to  give  detailed  accounts  of 
the  many  other  solutions  that  have  been  used;  let  it 
suffice  to  mention  in  brief  a  few  : — 

M.  de  Ruolz  has  employed, 

1.  Cyanuret  of  gold,  dissolved  in  simple  cyanuret  of 
potassium  ; 

2.  Cyanuret  of  gold,  dissolved  in  the  yellow  ferro- 
cyanuret ; 

3.  Cyanuret  of  gold,  dissolved  in  the  red  ferro- 
cyanuret  of  potassium; 

4.  Chloride  of  gold  dissolved  in  the  same  cyanurets ; 

5.  Double  chloride  of  gold  and  potassium  dissolved 
in  the  cyanuret  of  potassium ; 

6.  Double  chloride  of  gold  and  sodium  dissolved  in 
soda;* 

7.  Sulphur et  of  gold  dissolved  in  neutral  sulpliuret  of 
potassium. 

The  latter  is  said  to  be  singularly  valuable. 

He  uses  cyanuret  of  silver  in  yellow  ferrocyanuret 
of  potash.  Where  6  cells  in  series  are  required  for 
gilding,  4  are  sufficient  for  plating. 

128.  He  effects  platinating  with  the  double  chloride 
of  platinum  and  potassium  in  caustic  potash,  with  the 
same  ease  and  facility  as  plating  and  gilding ;  but  when 


*  Tlie  analogous  salt  of  potash  does  not  succeed. 


SOLUTIONS. 


37 


he  used  cyanuret  solutions  of  platinum,  like  those  of 
gold  or  silver,  it  required  one  or  two  hundred  times  the 
duration  of  the  experiment  to  produce  a  corresponding 
result. 

Lead  is  precipitated  from  oxide  of  lead  dissolved  in 
potash. 

Tin  is  deposited  on  iron  and  zinc,  &c,  from  a  solu- 
tion of  oxide  of  tin  in  potash,  or  tin  in  cream  of  tartar; 
which  latter  is  the  solution  employed  for  tinning  pins, 
the  process  being  in  truth  an  electrical  one ;  for  the 
pins  and  the  tin  are  thrown  into  the  liquid,  where  tlie 
latter  receive  a  coating. 

Zinc  is  deposited,  especially  on  iron ;  the  solution  is 
not  named.*  Elkington's  solution  for  zincing  is  given 
in  the  sequel  (§  138). 

129.  M.  Boettiger  uses  for  gilding  one  part  of  chlo- 
ride of  gold,  as  neutral  as  possible,  and  100  parts  water, 
in  which  he  allows  the  action  to  be  repeated  about  half- 
a-dozen  times,  of  a  minute's  duration  each,  and  washes 
the  article  between  each  operation  with  fine  linen  in  pure 
water.  For  platinating,  he  has  a  corresponding  solution 
of  platinum.  He  has  also  employed  one  part  of  chloride 
of  platinum,  100  parts  water,  and  8  parts  hydrochlorate 
of  soda;  or  one  part  ammoniacal  chloride  of  platinum, 
dissolved  with  8  parts  of  sal-ammoniac,  in  32  or  40  parts 
of  water.  The  latter  solutions  are  used  without  the 
voltaic  current  to  give  a  thin  coating ;  which  may  doubt- 
less be  increased  by  the  voltaic  action. 

130.  Mr.  Woolrich  uses  the  following  solutions  : — 


*  Vide  Les.  Archives,  June  7,  1842. 


38 


ELECTROTYPE  MANIPULATION. 


He  first  prepares  what  he  terms  the  solvent,  or  sul- 
phite of  potash,  thus:  28  lbs.  of  the  best  pearlash, 
and  30  lbs.  of  water  are  boiled  in  an  iron  vessel ;  the 
solution  is  allowed  to  cool,  and  is  then  filtered.  To  this 
are  added  14  lbs.  of  distilled  water  \  sulphurous  acid  gas* 
is  then  passed  into  the  liquor  until  it  becomes  saturated; 
and  the  liquor  is  filtered  for  use. 

Silvering -liquor. — 12  oz.  of  crystallized  nitrate  of 
silver  are  dissolved  in  3  lbs.  of  distilled  water.  The 
solvent  just  described  is  gradually  added,  so  long  as  a 
whitish  precipitate  falls.  The  supernatant  liquor  is 
poured  off,  and  the  precipitate  washed  with  distilled 
water.  To  the  washed  precipitate  is  added  as  much  of 
the  solvent  as  will  dissolve  it ;  and  then  ith  part  more, 
so  that  the  solvent  may  be  in  excess.  After  being  well 
stirred,  and  allowed  to  remain  for  24  hours,  the  liquor 
is  ready  for  use. 

Gilding -liquor. — Four  oz.  troy  of  fine  gold  are 
dissolved  in  a  mixture  of  11  fluid  oz.  nitric  acid,  13 
muriatic  acid,  and  12  distilled  water;  the  solution  is 
evaporated  and  crystallized;  and  the  crystals  are  dis- 
solved in  1  lb.  of  distilled  water :  the  gold  is  then  pre- 
cipitated by  pure  magnesia,  the  precipitate  is  first  washed 
with  distilled  water  acidulated  with  nitric  acid,  and  then 
with  water  alone.    To  the  washed  precipitate  is  added 


*  This  gas  may  be  obtained  by  applying  heat  to  a  flask  con- 
taining sulphuric  acid  and  pieces  of  well-burned  charcoal.  The 
gas  should  be  passed  through  water  to  free  it  from  any  acid  it 
may  have  carried  over. 


SOLUTIONS. 


39 


enough  solvent  to  dissolve  it,  and  jth  more.  After  being 
stirred  and  remaining  24  hours,  it  is  fit  for  use. 

Coppering -liquor. — 7  lbs.  of  sulphate  of  copper  are 
dissolved  in  30  lbs.  of  distilled  water,  and  to  this  is 
added  solution  of  carbonate  of  potassa  until  precipitation 
ceases.  The  precipitate  is  washed,  and  dissolved  in  the 
solvent  as  before,  one-third  more  being  added.  This 
must  stand  for  twenty-four  hours,  like  the  others. 

131.  Mr.  Tuck  has  prepared  the  following  liquid. 
He  dissolves  70  parts  by  weight  of  bicarbonate  of  am- 
monia in  distilled  water,  to  which  he  adds  by  weight  56 
parts  of  sulphate  of  silver,  or  134  parts  of  cyanide  of 
silver,  and  boils  the  liquor  until  the  silver  salt  is  entirely 
dissolved.  The  strongest  solution  that  he  has  employed 
was  in  the  proportion  of  half  an  ounce  of  sulphate  of 
silver  and  107  grs.  of  bicarbonate  of  ammonia  to  a  pint 
of  distilled  water. 

132.  Mr.  Briant,  of  St.  Petersburg,  gives  the  fol- 
lowing preparation  of  gold  solution,  as  superior  to  any 
other.  He  makes  a  solution  of  6  J  solotnik  (428  grs.) 
of  gold  in  aqua  regia  (nitro-muriatic  acid),  by  aid  of  a 
sand-bath ;  he  boils  it  down  to  one-fourth,  when  crystal- 
lization occurs;  he  evaporates,  but  not  to  dryness.  The 
crystals  are  then  dissolved  in  hot  water,  and  half  a 
pound*  of  powdered  magnesia  dissolved  in  water  is 
added.  It  is  filtered  warm ;  if  the  liquor  is  dark,  the 
magnesia  is  not  all  dissolved,  when  it  must  be  boiled 


*  A  Russian  pound,  of  96  solotniks,  is  equal  to  6318.5  grs. 
Eng. 


40 


ELECTROTYPE  MANIPULATION. 


again.  It  is  now  washed  in  the  filter,  and  the  hydrated 
oxide  of  gold  remaining  in  the  filter  is  placed  in  a  flask, 
and  on  it  is  gradually  poured  half  a  Russian  pound  of 
nitric  acid;  after  the  effervescence  ceases,  it  is  again 
filtered  and  well  washed;  and  the  chocolate-colored  resi- 
duum is  boiled  in  a  hot  prepared  solution  of  1  lb.  22 
solotnik  (7766  grs.)  of  prussiate  of  potash;  when  it 
boils,  10  solotnik  (6.58  grs.)  of  caustic  potash,  previously 
dissolved  in  cold  water,  are  added,  and  well  mixed.  When 
cool,  the  solution  is  filtered  for  use ;  the  sediment  now 
remaining  in  the  filter  is  oxide  of  iron. 

133.  Major  Von  Jewreinoff  gives  the  following  silver 
solution  :  4  parts  of  dry  powdered  prussiate  of  potash 
are  well  incorporated  in  a  mortar  with  1J  parts  of  pure 
potash,  and  are  melted  in  a  closed  vessel  till  the  product 
becomes  transparent  and  dazzling  white.  Chloride  of 
silver,  prepared  by  throwing  salt  into  a  solution  of 
nitrate  of  silver,  is  dissolved  in  this  solution  and  fil- 
tered for  use. 

134.  A  writer  in  the  3fec7ianics'  Magazine,  Mr. 
Eockline,  has  used  the  following  solution  :  Oxide  of 
silver  is  dissolved  in  citric  acid;  the  solution  is  evapo- 
rated to  dryness,  and  the  residual  salt  is  exposed  in  a 
tube  to  212°  Fahr.,  when  a  current  of  dry  hydrogen  is 
passed  over  it  for  a  few  minutes.  The  salt  is  then  dis- 
solved for  use  in  cold  water.  He  says  this  solution 
must  not  be  heated. 

135.  Other  applications  of  Electro-gilding.  —  On 
the  continent,  and  here  also,  this  art  has  been  rendered 
available  in  gilding  the  springs  and  works  of  chrono- 


SOLUTIONS. 


41 


meters';  and  one  experimentalist,  M.  Perrot,  has  "  un- 
dertaken to  gild  at  the  same  time  all  the  movements  of 
a  watch — to  gild  them,  not  only  in  their  places,  but 
while  in  motion.*  M.  Boettiger,  to  whom  I  have  al- 
ready (§  129)  alluded,  has  employed  for  gilding  the 
bichloride  of  gold,  and  has  prepared  copper  surfaces, 
by  first  depositing  platinum  upon  them.  M.  Hamman, 
an  engraver  of  Geneva,  has  deposited  a  coat  of  gold 
instead  of  one  of  varnish  on  plates  intended  for  ordinary 
etching,  and  has  traced  the  design  most  accurately, 
through  this  exceedingly  delicate  layer. 

136.  Electro-gilding  has  been  successfully  applied  in 
protecting  and  permanently  fixing  Daguerreotype  pic- 
tures. It  is  well  known  that  thin  films  of  gold  are 
transparent.  A  thin  film  is  therefore  deposited  upon 
the  surface  of  the  finished  plate,  and  effectually  secures 
the  picture  from  destruction ;  while  it  does  not  in  the 
least  hide  it  from  the  eye,  or  detract  from  its  beauty. 
The  silver  surface  of  Daguerreotype  plates  is  greatly 
improved  by  depositing  upon  them  a  thin  film  of  silver, 
and  subsequently  polishing  them  according  to  the  usual 
plan. 

137.  Daguerreotype  Plates.  - —  The  art  of  electro- 
plating may  be  made  available  in  preparing  Daguerre- 
otype plates.  The  lovers  of  this  attractive  art  (which 
is  so  well  explained  in  the  third  and  fourth  numbers  of 
this  series  of  Manuals),  may  thus  experiment  upon 
plates  of  their  own  preparation.    They  may  be  prepared 


*  Vide  Arch,  de  l'Electricite,  No.  I.  p.  276. 

11 


42 


ELECTROTYPE  MANIPULATION. 


in  two  ways  :  either  by  plating  a  burnished  and  pre- 
pared copper  plate ;  or  by  depositing  silver,  with  due 
precautions,  on  a  burnished  plate,  and  afterwards  back- 
ing up  with  copper.  The  latter  is  the  most  effectual, 
especially  to  those  who  are  not  skilled  in  the  plans 
adopted  by  the  artisan  for  the  treatment  of  burnished 
surfaces. 

138.  Electro-zincing. — Messrs.  Elkington  have  pa- 
tented a  process  for  applying  zinc  to  iron,  in  order  to 
protect  it  from  the  atmosphere.  They  say  that  the  best 
and  cheapest  solution  is  the  sulphate  of  zinc,  of  which 
they  dissolve  a  pound  in  a  gallon  of  water ;  and  elec- 
trolyze  it  with  a  battery  of  feeble  power.  This  is  not 
the  well-known  galvanized  iron.  The  latter  is  prepared 
by  immersing  the  iron  in  melted  zinc ;  which  process 
gives  to  it  a  coat  of  the  latter  metal,  that  acts  as  a  most 
valuable  protection  against  the  corrosive  influences 
of  the  atmosphere,  as  will  be  seen  in  the  fifth  of  these 
Manuals,  which  treats  upon  the  "  Electric  Telegraph/' 
for  which  it  is  extensively  used. 

139.  Reduction  of  Alloys. — This  has  been  long 
deemed  impracticable ;  but  recent  experiments  have 
proved  that  it  is  possible.  M.  de  Ruolz  was  the  first  to 
deposit  a  galvanic  film  of  bronze  on  other  metals,  by 
dissolving  cyanide  of  copper  and  oxide  of  tin,  in  certain 
proportions,  in  cyanide  of  potassium,  and  allowing  a 
constant  battery  to  act  upon  the  solution.  Professor 
Majocchi  reports  the  deposition  of  an  alloy  of  lead  and 
iron,  which  he  says  is  much  harder  than  lead,  and 
melts  at  a  much  higher  heat.    Protosulphate  of  iron  is 


SOLUTIONS  AND  APPARATUS. 


43 


added  to  a  solution  of  lead  and  nitric  acid,  in  such 
quantity  that  the  resulting  solution  shall  not  be  very 
concentrated.  Professor  Jacobi  obtained  films  of  brass 
by  preparing  solution  of  cyanide  of  potassium,  and 
throwing  in  copper,  from  a  positive  plate  of  copper,  and 
then  zinc  from  a  positive  plate  of  zinc ;  after  a  certain 
time  brass  was  given  off.  I  have  repeated  Jacobi' s  ex- 
periments, and  made  many  hundred  original  ones,  with 
very  various  solutions,  to  discover  whether  it  were  pos- 
sible to  obtain  a  solution  that  should  continue  to  give 
off  brass.  I  have  obtained  deposits  of  most  brilliant 
brasses,  but  all  the  solutions  yet  operated  upon  have 
failed  to  retain  their  properties  beyond  a  day  or  two  : 
new  chemical  combinations  occur. 

The  following  are  Mr.  Joseph  Steele's  processes  : — 
Electro-tinning. — Warm  75  gallons  of  distilled 
water ;  in  parts  of  it  dissolve  separately  60  lbs.  of  com- 
mon soda,  and  strain ;  15  lbs.  of  Russian  or  American 
potash,  and  strain  \  5  lbs.  caustic  potash  j  2  oz.  cyanide 
of  potassium  ;  2  oz.  acetate  of  zinc  ;  16  lbs.  bioxide  of 
tin  :  mix  the  first  three  solutions,  and  then  add  the 
last  three,  and  let  the  whole  stand  for  two  or  three 
hours.  Use  a  piece  of  tin  as  the  positive  plate  in  the 
decomposition  cell. 

Electro-brass. — Warm  6  gallons  of  distilled  water ; 
dissolve  separately  2?  lbs.  American  potash;  2 J  oz. 
powdered  acetate  of  copper,  previously  mixed  with  half 
a  pint  of  strong  spirits  of  ammonia ;  4  or  5  oz.  sulphate 
of  zinc ;  2  oz.  cyanide  of  potassium.    For  copper  de- 


44 


ELECTROTYPE  MANIPULATION. 


posit,  leave  out  sulphate  of  zinc.  It  is  better  to  let 
the  mixture  stand  for  three  or  four  days  before  using. 

140.  Electrolysis  of  fused  Compounds. — Mr.  Arthur 
Wall  has  a  patent  for  purifying  iron  ore  from  sulphur, 
phosphorus,  and  other  such  elements,  by  applying  a 
powerful  voltaic  current  to  the  metal  while  in  a  state  of 
fusion,  either  when  it  is  in  the  smelting  furnace,  or 
while  it  is  in  the  moulds;  and  he  prefers  continuing  the 
current  until  the  metal  is  solidified.  In  reference  to 
these  experiments,  Dr.  Ure  is  understood  to  have  stated 
that  a  current  was  passed  through  a  rod  of  soft  iron,  at 
a  moderate  heat,  and  in  a  few  hours  it  was  converted 
into  steel. 

141.  Mr.  Napier  has  patented  a  process  for  reducing 
copper  from  its  ore  by  the  aid  of  an  electric  current. 
Native  sulphuret  of  copper,  for  instance,  is  roasted  in 
the  usual  way,  and  is  then  melted  with  lime  and  soda  as 
fluxes ;  the  pot  is  now  so  connected  with  a  battery  as  to 
be  the  negative  pole,  or  place  for  receiving  deposits ;  and 
a  plate  of  iron  connected  with  the  positive  pole  is  thrust 
beneath  the  surface  of  the  fluid  mass ;  a  solid  mass  of 
copper  is  soon  found  deposited  on  the  inner  surface  of 
the  pot,  the  quantity  of  which  is  stated  to  be  more  than 
a  dozen  times  that  of  the  chemical  equivalent  of  the 
electric  action. 

142.  Mr.  Parker  has  a  patent  for  plating  and  gilding 
by  means  of  fused  iodides,  chlorides,  and  phosphates 
of  the  metals.  As  an  example,  he  takes  6  lbs.  of 
chloride  of  silver,  fused  in  a  silver  or  an  enamelled 
iron  vessel ;  when  fluid,  he  immerses  in  it  the  article  to 


SOLUTIONS  AND  APPARATUS. 


45 


be  plated,  which  is  in  connection  with  the  negative  end 
of  the  battery,  and  a  plate  of  silver  connected  with  the 
positive  end  5  to  increase  the  quantity  of  fluid,  he  some- 
times adds  to  it  from  3  to  10  lbs.  of  iodide  of  potassium, 
or  even  the  iodide  of  mercury  or  copper,  in  the  propor- 
tion of  1  or  2  lbs. 

For  a  gold  fluid  he  takes  20  oz.  of  iodide  of  gold 
and  80  oz.  of  iodide  of  potassium  or  sodium,  which  he 
subjects  to  similar  treatment,  using,  of  course,  a  gold 
instead  of  a  silver  plate. 

143.  Mr.  Ritchie  has  a  patent  for  extracting  copper 
from  its  ore  by  a  very  simple  voltaic  arrangement.  He 
dissolves  the  calcined  copper  ore  in  dilute  sulphuric  acid, 
and  places  the  solution  in  a  large  rectangular  vessel ) 
on  the  upper  surface  of  this,  he  pours  a  mixture  of  two 
parts  water  and  one  saturated  solution  of  sulphate  of 
iron,  taking  care  that  mixture  does  not  take  place  with 
the  lower  liquid ;  he  then  places  an  iron  plate  as  a  ge- 
nerating metal  in  the  iron  solution,  and  a  plate  of  lead 
in  the  copper  solution  to  receive  the  deposit,  connecting 
the  lead  and  iron  with  a  wire. — It  is  also  stated  that, 
by  this  process,  galvano-plastic  objects  may  be  easily 
obtained  on  a  large  scale. 

144.  Magneto-electro  Machine. — We  are  here  called 
upon  to  notice  another  means  of  obtaining  electric 
currents,  inasmuch  as  it  has  been  successfully  applied 
by  Mr.  Woolrich  of  Birmingham,  to  gilding  and  plating. 
A  magnet  has  the  property  of  generating  electric  cur- 
rents in  all  metals  that  are  in  motion,  within  the  sphere 
of  its  influence ;  but  only  while  they  are  in  motion. 

11* 


46 


ELECTROTYPE  MANIPULATION. 


By  proper  adjustment,  these  effects  may  be  exalted. 
In  practice,  powerful  horseshoe  magnets  are  employed, 
and  great  lengths  of  silk-covered  copper  wire,  wound 
upon  bobbins  with  iron  cores,  are  made  to  revolve  in 
front  of  the  magnetic  poles,  by  the  action  of  a  small 
steam-engine.  Arrangements  are  made  to  intercept 
the  currents  at  the  ends  of  the  coils,  and  to  convey 
them  into  a  trough  containing  the  metallic  solution. 
By  sliding  a  keeper  along  the  magnet  to  various  dis- 
tances, the  force  of  the  current  is  modified.  A  single 
machine  will  reduce  five  ounces  of  gold  per  hour.  A 
large  machine  was  constructed  that  was  calculated  to 
have  deposited  twenty  ounces  per  hour;  but  it  is 
thought  to  have  been  damaged  by  other  experiments. 
The  steam  power  for  driving  twenty  such  machines  is 
stated  to  cost  only  15s.  per  week — the  wear  and  tear  is 
small.  But,  all  things  considered,  the  Messrs.  Elking- 
ton  have  found  it  more  profitable  to  continue  the 
employment  of  the  Voltaic  Battery  in  their  extensive 
works. 

Dr.  Braun  is  employing,  it  is  said,  one  of  these 
machines  at  Rome,  for  producing  electrotype  copies 
from  casts  of  the  works  of  art  in  that  city,  as  referred 
to  hereafter  (§  181). 


DEPOSITION  OF  OXIDES  OF  METALS  ON  METALS.  47 


II.— DEPOSITION  OF  THE  OXIDES  OF 
METALS  ON  METALS. 

145.  Metallo-cJiromes. — Hitherto  we  have  been  con- 
sidering the  deposition  of  metal  on  metal ;  it  remains  to 
give  a  familiar  description  of  the  mode  of  depositing 
metal  in  union  with  oxygen,  i.  e.  a  metallic  oxide  on 
metals.  The  most  beautiful  experiments  of  this  kind 
are  those  described  by  Nobili,*  and  recently  repeated 
and  considerably  modified  by  Mr.  GJ-assiot.f  The  pro- 
ductions are  known  by  the  name  of  metallo-chromes. 
A  saturated  solution  of  acetate  of  lead  is  prepared,  and 
poured  into  a  shallow  vessel,  in  which  has  been  placed 
a  highly-polished  steel  plate.  A  wire  from  the  positive 
end  of  a  series  of  three  or  four  Daniells,  is  made  to 
touch  the  plate.  Then,  if  another  wire  from  the  nega- 
tive end  of  the  series  is  held  in  the  solution,  over  the 
plate,  a  small  tinted  circle  makes  its  appearance  on  the 
polished  surface  beneath  the  wire,  and  rings  of  color 
of  the  most  brilliant  hues  rise  from  the  centre  and 
expand  to  the  circumference.  The  colors  commence 
with  silver-blond,  and  progress  onwards  to  fawn-color, 
and  thence  through  various  shades  of  violet  to  the  in- 
digos and  blues ;  then  through  pale  blue  to  yellow  and 
orange ;  thence  through  lake  and  bluish  lake,  to  green 
and  greenish  orange,  and  rose  orange  ;  thence  through 

*  Scient.  Memoirs,  vol.  i.  art.  5. 

f  Proceed.  Elec.  Soc.  Dec.  17,  1839,  4to. 


48 


ELECTROTYPE  MANIPULATION. 


greenish  violet  and  green,  to  reddish  yellow  and  rose  lake, 
which  is  the  highest  color  on  the  chromatic  scale. 

146.  Colored  figures  of  varied  character  are  obtained 
by  modifying  the  shape  of  the  electrode  connected  with 
the  negative  end  of  the  battery;  using  instead  of  a  point 
a  slip  of  metal,  a  disk,  a  ring,  a  convex  or  a  concave  cir- 
cle, a  cross,  or  other  pattern.  By  the  employment  of  a 
large  disk,  and  small  steel  plates,  and  by  very  careful 
manipulation,  a  uniform  tint  may  be  given  to  each  plate, 
and  the  chromatic  scale  of  forty-four  colors  may  be 
obtained.  For  this  purpose  each  experiment  must  be 
timed  by  a  pendulum,  and  one  second  being  given  to 
the  first  plate,  the  duration  for  the  rest  must  increase 
by  a  second  for  each.  It  is  absolutely  essential  in  ope- 
rations of  such  extreme  delicacy  that  all  the  plates  be  of 
the  same  thickness,  so  that,  when  adjusted  to  their  posi- 
tion, they  may  remain  at  the  same  distance  from  the 
disk.  Many  more  than  forty-four  specimens  will  be 
produced,  which  must  be  placed  in  order,  and  the  simi- 
lar tints  rejected.  The  spoiled  plates  are  cleaned  with 
fine  emery  paper. — The  best  metallo-chromes  are  ob- 
tained by  cutting  a  star  or  other  pattern  in  card,  and 
placing  the  pattern  on  the  plate,  beneath  a  convex  or  a 
concave  disk. 

The  colors  arise  from  the  very  thin  films  of  oxide  of 
lead  that  are  deposited  on  the  steel  plates,  and  are  due 
to  an  analysis  of  light,  similar  to  what  occurs  in  a  soap- 
bubble,*  or  in  the  film  of  air  between  a  lens  and  a  plate 


*  The  best  mode  of  making  a  soap-bubble  is  to  place  a  piece 
of  soap,  about  as  large  as  a  pea,  in  a  six-ounce  vial,  one-third 


DEPOSITION  OF  OXIDES  OF  METALS  ON  METALS.  49 


of  glass,  closely  pressed  together.  No  practical  use  had 
been  made  of  these  films. 

147.  Deposition  of  Oxide  of  Lead. — M.  Becquerel 
has  described*  a  means  of  coating  metals  with  oxide  of 
lead  and  oxide  of  iron,  for  the  purpose  of  protecting 
them  from  the  action  of  the  air.  He  uses  a  potash  solu- 
tion of  lead,  which  is  prepared  by  dissolving  200  gram- 
mesf  of  caustic  potash  in  two  litres  J  of  distilled  water, 
and  adds  to  it  150  grammes  of  protoxide  of  lead — the 
litharge  of  commerce. — It  is  boiled  for  half  an  hour,  and 
after  being  allowed  to  settle,  is  diluted  for  use  with  its 
volume  of  water.  Some  of  the  solution  is  poured  into 
a  porous  tube,  which  is  placed  in  a  vessel  containing  water 
acidulated  with  one-twentieth  its  weight  of  nitric  acid. 
The  nitric  acid  contains  a  platinum  plate,  connected 
with  the  negative  or  zinc  end  of  a  single  cell  of  Daniell's 
battery ;  and  the  article  to  be  coated  with  oxide  of  lead, 
as,  for  instance,  a  plate  of  iron,  is  placed  in  the  solution 
of  lead,  and  connected  with  the  copper  of  the  battery. 
In  a  few  minutes  the  plate  is  covered  with  a  coating  of 
peroxide  of  lead,  which  arises  from  the  union  of  the 
oxygen  with  the  protoxide  of  the  solution.  The  adhe- 
rence is  very  strong,  and  if  the  article  has  been  well  pre- 


filled  with  water ;  the  vital  is  to  be  then  placed  in  a  vessel  of 
water,  and  the  water  to  be  boiled.  When  the  vial  gives  off  steam 
pretty  freely,  it  is  to  be  corked,  and  then  removed  and  sealed 
immediately.  A  horizontal  film  of  soap  may  at  any  time  be 
made  by  shaking  the  vial. 

*  Vide  Comptes  Rendus,  July  3,  1843. 

f  A  gramme=15J  gr.  troy.  J  A  litre=61  cub.  in. 


50 


ELECTROTYPE  MANIPULATION. 


pared  (§  116,  &c),  will  sustain  the  action  of  the  burn- 
isher. The  color  of  the  deposit  is  black  with  a  brown- 
ish tinge;  if  the  action  is  allowed  to  continue,  it  assumes 
the  tint  of  yellow  ochre.  The  liberation  of  hydrogen 
on  the  platinum  plate  is  a  sign  that  things  are  going 
on  well.  The  solution  must  not  be  used  to  exhaustion, 
but  be  replaced  by  fresh,  after  perhaps  a  dozen  hours  of 
action. 

148.  Deposition  of  Oxide  of  Iron. — An  ammoniacal 
solution  of  iron  is  used  for  obtaining  a  deposit  of  the 
peroxide.  A  hot  solution  of  protosulphate  of  iron  is 
prepared,  and  placed  in  the  receiver  of  an  air-pump, 
to  abstract  from  it  all  air :  a  solution  of  ammonia  is 
likewise  deprived  of  air,  and  a  little  more  than  is  suf- 
ficient to  dissolve  the  protoxide  of  iron  is  poured  into 
the  former  solution.  This  solution  is  used  in  the  same 
manner  as  that  of  lead,  described  in  the  preceding 
paragraph,  namely,  in  a  diaphragm  decomposition  cell; 
but  care  must  be  taken  to  keep  it  covered  from  the  air, 
which  has  so  great  a  power,  on  account  of  the  oxygen 
it  contains,  of  converting  the  protoxide  into  a  peroxide. 
A  few  minutes  suffice  for  the  operation.  The  deposit 
of  peroxide  is  of  a  brownish-red  color,  having  somewhat 
the  appearance  of  precipitated  copper;  if  the  action 
continues,  the  color  becomes  darker,  and  finally  it  is 
deep  violet.  The  oxide  will  endure  the  burnisher. 
If  the  action  is  carried  on  at  an  elevated  temperature, 
the  adhesion  is  greater,  because  the  contraction  of  the 
expanded  metal  binds  the  film  more  closely.  The  use 
of  the  diaphragm  in  these  operations  is  to  prevent  the 


ELECTRO-ETCHING. 


51 


solution  from  becoming  exhausted;  for  if  the  experiment 
were  carried  on  under  ordinary  circumstances,  the  de- 
position of  metal  at  the  one  electrode,  and  oxide  of 
metal  at  the  other,  would  very  soon  deprive  the  solution 
of  its  contents. 

IH.  ELECTRO-ETCHING. 

149.  The  results  hitherto  treated  on,  have  been  (with 
the  exception  of  the  deposition  of  the  oxides),  all  ob- 
tained at  the  negative  metal;  but  there  is  a  class  of 
results  of  no  inconsiderable  importance  to  be  obtained 
at  the  other  terminal. 

The  plates  of  copper,  in  the  decomposition  cell,  in 
connection  with  the  copper  of  the  battery,  have  been 
described  as  combining  gradually  with  the  oxygen 
released  there,  and  being  eventually  consumed ;  so 
likewise  the  plates  of  silver  or  gold,  which  occupy  the 
same  relative  position,  are  in  a  similar  manner  con- 
sumed. But  as  the  varnish  (§  31),  placed  on  moulds, 
effectually  shields  the  parts  protected  by  it,  from  the 
effects  of  electrolytic  action,  so  also  may  the  copper 
plates,  or  the  plates  of  any  metal  connected  with  the 
positive  end  of  the  battery,  be  protected,  and  the 
destructive  action  localized  at  pleasure. 

150.  If,  for  instance,  plates  of  copper  be  covered 
on  any  part  of  their  surface  with  a  stratum  of  varnish, 
that  part  will  be  excluded  from  the  line  of  action,  while 
all  else  is  being  consumed.    Advantage  has  been  taken 


52 


ELECTROTYPE  MANIPULATION. 


of  this,  by  coating  plates  with  proper  composition  and 
then  tracing  through  it  any  design,  of  which  an  etching 
is  required.  The  plate  in  this  condition  is  submitted 
to  the  action  of  the  nascent  oxygen,  and  the  surface  is 
readily  and  effectually  etched.  There  is  some  superio- 
rity too  possessed  by  this  method,  over  the  ordinary 
etching  by  the  use  of  nitric  acid  )  for  the  operation 
can  be  conducted  with  considerable  regularity ;  it  can 
be  rendered  a  slow  or  a  speedy  process ;  and  the  result 
can  be  taken  out,  from  time  to  time,  to  be  examined, 
and  can  be  re-submitted  in  a  moment.  In  fact,  of 
so  much  importance  has  this  mode  of  etching  been 
deemed,  that  it  is  already  one  amongst  the  many 
applications  of  this  principle  for  which  a  patent  has 
been  obtained. 

151.  Process  of  Electro-etching. — Take  a  burnished 
copper  plate,  and  solder  to  it  a  stout  wire :  heat  the 
plate,  and  rub  its  surface  with  etching-ground,* 
wrapped  in  silk  ;  be  careful  to  obtain  an  even  coating ; 
then  smoke  the  covered  surface  over  the  flame  of  a 
candle.  Varnish  the  back  of  the  plate,  as  well  as  the 
wire,  with  shell-lac.  Trace  the  design  through  the 
etching-ground  with  a  fine  point.  This  done,  place  it 
in  a  decomposition  cell,  and  connect  it  with  the  copper 
of  a  DanielFs  or  other  cell,  placing  opposite  to  it  a 
plate  of  somewhat  similar  size )  after  the  lapse  of  ten 
minutes  remove  it,  and  "  stop  out"  the  fine  parts  with 


*  Etching-ground  consists  of  asphalte,  wax,  black  pitch, 
and  Burgundy  pitch. 


ELECTRO-ETCHING. 


53 


Brunswick  black;  return  it  to  the  decomposition  cell 
for  a  second  ten  minutes ;  and  again  stop  out  the  half 
tints;  again  submit  it  to  action  for  ten  minutes,  and 
the  operation  is  complete.  Remove  the  etching-ground 
by  means  of  heat,  and  a  perfect  engraving  will  be  found 
on  the  plate.  The  exact  duration  of  the  several  opera- 
tions, as  well  as  their  number,  must  be  regulated  accord- 
ing to  circumstances.  Electro-etching  is  an  interesting 
experiment  for  the  lecture-table.  At  the  commencement 
of  a  lecture,  I  have  submitted  a  plate  to  electric  action, 
and,  before  the  hour  has  expired,  have  distributed  proof 
impressions. 

152.  An  etching-ground  of  gold  may  be  applied  by 
submitting  a  copper  plate,  well  varnished  on  the  back, 
to  the  action  of  an  electric  current  passing  through  a 
solution  of  the  cyanide  of  gold.  When  a  perfect  coating  is 
obtained,  the  plate  is  removed ;  and  the  design  is  etched 
with  a  fine  point  through  the  gold  film.  The  plate  is 
then  submitted  to  the  action  of  the  battery,  as  before  ; 
and  as  the  oxygen,  released  there,  combines  with  the 
copper,  but  not  with  the  gold,  the  design  is  permanently 
etched. — The  process  of  etching  is  very  speedily  effected; 
and  must,  therefore,  be  very  carefully  attended  to,  lest, 
by  proceeding  too  far,  the  plate  be  spoiled. 

153.  Electro-etching  Daguerreotype  Plates. — In  the 
description  last  given,  the  artist's  hand  must  first  trace 
the  design,  before  the  electric  force  will  engrave  for 
him ;  but  Mr.  Grove  has  described  a  process*  by  which 


*  Vide  Proceed.  Elec.  Soc.  vol.  i.  p.  94.  Aug.  17,  1841. 


54 


ELECTROTYPE  MANIPULATION. 


the  pencil  of  nature  does  all  the  work.  He  lias  taken 
Daguerreotype  plates  —  those  beautiful  productions 
" drawn  by  light/'  and  having  submitted  them  to  the 
still  further  operation  of  Nature's  laws,  has  succeeded  in 
"  engraving  by  electricity." 

154.  Though  this  process  has  not  been  perfected,  so 
far  as  to  produce  plates  fitted  in  all  respects  for  the 
printer,  yet,  as  it  is  a  very  important  and  instructive 
application  of  the  subject  on  which  we  treat;  and  as 
it  furnishes,  though  not  for  the  printer  yet  for  the  elec- 
trotypisty  plates  from  which  he  can  obtain  perfect  im- 
pressions, and  these  to  any  extent,  it  claims  especial 
notice  in  this  treatise. 

155.  Nature  of  Daguerreotype  Pictures. — The  dark 
portions  of  these  pictures  are  considered  to  be  silver, 
and  the  light  portions  mercury ;  and  hence,  if  they  are 
placed  in  a  solution,  whose  liberated  element  shall  act 
on  one  of  these  metals,  and  not  on  the  other;  or  if  they 
are  submitted  to  a  solution,  the  liberated  element  of 
which  combines  more  with  one  than  the  other,  the  result 
will  be  an  etching. 

156.  Hydrochloric  acid,  diluted  with  half  its  bulk  of 
water,  has  been  employed.  From  hydrochloric  acid, 
hydrogen  is  released  at  the  negative  plate;  and  the  great 
object  is  to  dispose  of  it  regularly,  and  as  speedily  as  may 
be;  for,  if  any  hydrogen  adheres  to  the  surface  of  this 
plate,  the  surface  of  the  plate  to  be  etched,  where  it  is 
opposed  to  this,  will  furnish  an  irregular  result.  The 
best  plates  for  parting  with  the  nascent  hydrogen,  are 
platinized  silver,  or  platinized  platinum.    The  distance 


ELECTRO-ETCHING. 


55 


between  the  two  plates  (which  are,  of  course,  placed 
parallel)  should  be  about  the  fifth  of  an  inch,  which  is 
near  enough  to  insure  uniformity  of  action,  and  not  so 
near  as  to  allow  the  escaping  hydrogen  to  interfere  with 
the  result. 

157.  In  a  process  so  delicate  as  that  of  etching  out 
the  microscopic  delineations  on  these  plates,  due  regard 
must  be  paid  to  the  relation  between  the  size  of  the 
generating  pairs  and  the  size  of  the  plates  themselves. 
The  best  mode  is  to  have  the  generating  pair  and  the 
decomposing  pair  of  one  size,  or  nearly  so;  and,  as  the 
solution  employed  will  give  up  its  elements  with  a  feeble 
current,  one  generating  cell  is  enough.  Prof.  Grove 
used  a  single  pair  of  the  nitric  acid  batter?/;  but  any 
other  will  produce  the  desired  result.  The  time  of  action 
depends  on  the  nature  of  the  generating  cell  employed. 
With  the  nitric  acid  battery  (which  is  very  energetic  in 
its  action),  the  effect  was  produced  in  from  25  to  30 
seconds.  With  other  arrangements  it  will  be  longer  \ 
and,  possibly,  as  it  is  accomplished  more  slowly,  the 
result  will  be  more  definite ;  and  the  experiment  will  be 
less  liable  to  fail. 

158.  Having  determined  these  several  points,  and 
shown  the  reasons  on  which  they  are  based — (and  I  always 
wish  to  furnish  reasons  for  all  that  is  done ;  for  when  a 
man  acts  by  mere  directions,  and  arrives  at  ends  he 
knows  not  why,  I  am  well  assured  that  his  interest  in 
the  subject  will  soon  be  dissipated,  and  his  path,  instead 
of  being  pleasing  and  bright,  will  be  dull  and  gloomy) — 
the  next  arrangement  is  to  prepare  a  wooden  frame  with 


56 


ELECTROTYPE  MANIPULATION. 


grooves  into  which  the  two  plates,  viz.,  the  Daguerreo- 
type* and  the  platinized  plate  can  slide,  so  as  to  remain 
firmly  fixed  in  the  required  position.  This  frame  is 
then  immersed  in  the  solution,  and  contact  is  made  with 
the  generating  cell  by  touching,  with  the  ends  of  the 
connecting  wires,  the  edgesf  of  the  plates ;  and  retain- 
ing them  in  contact  for  the  given  time.  "  The  plate 
is  then  removed,  and  well  rinsed  in  distilled  water,  and, 
if  the  silver  be  homogeneous,"  J  will  "  present  a  beautiful 
sienna-colored  drawing  of  the  original  design,  produced 
by  a  film  of  the  oxychloride§  formed.  It  is  now  placed 
in  an  open  dish,  containing  a  very  weak  solution  of 
ammonia,  and  the  surface  gently  rubbed  with  very  soft 
cotton,  until  all  the  deposit  is  dissolved;  as  soon  as 
this  is  effected,  it  should  be  instantly  removed,  and 
plunged  into  distilled  water,  and  carefully  dried.  The 


*  This  plate  must  be  well  varnished  on  its  back  and  edges. 

f  A  small  portion  of  varnish  is  removed  from  the  Daguerreo- 
type for  this  purpose. 

J  "It  is  very  necessary  that  the  silver  of  plates  subjected  to 
this  process  be  homogeneous.  Striae,  imperceptible  in  the 
original  Daguerreotype,  are  instantly  brought  out  by  the 
nascent  anion  (or  element  liberated  from  the  solution  at  the 
positive  pole) ;  probably  silver,  formed  by  voltaic  precipitation 
would  be  found  the  most  advantageous." — Prof.  Grove.  This 
extract,  illustrated  as  it  was  by  the  condition  of  the  prints  from 
some  of  the  etched  plates,  indicates  that  the  application  of 
electro-plating,  before  described  (J  137),  will  eventually  be 
found  of  some  service. 

§  Oxygen  from  the  water,  and  chlorine  from  the  acid,  are 
released  at  the  Daguerreotype  plate. 


ELECTRO-ETCHING. 


57 


process  is  now  complete,  and  a  perfect  etching  of  the 
original  design  will  be  observed;  this,  when  printed  from, 
gives  a  positive  picture,  or  one  which  has  its  lights  and 
shadows  as  in  nature ;  and  which  is  in  this  respect  more 
correct  than  the  original  Daguerreotype,  as  the  sides 
are  not  inverted :  printing  can  therefore  be  directly  read ; 
and  in  portraits  thus  taken,  the  right  and  left  sides  of 
the  face  are  in  their  proper  position." — "  There  is,  how- 
ever, ex  necessitate  rei,  this  difficulty  with  respect  to 
engravings  from  Daguerreotypes;  if  the  plates  be  etched 
to  a  depth  sufficient  to  produce  a  good  impression,  some 
of  the  finer  lines  of  the  original  must  inevitably  run  into 
each  other;  and  thus  the  chief  beauty  of  these  exquisite 
images  be  destroyed.  If,  on  the  other  hand,  the  process 
be  only  continued  long  enough  to  leave  an  exact  etching 
of  the  original  design,  which  can  be  done  to  the  minu- 
test perfection,  the  very  cleaning  of  the  plate  by  the 
printer  destroys  its  beauty;  and  the  molecules  of  the 
printer's  ink  being  larger  than  the  depth  of  the  etchings, 
a  very  imperfect  impression  is  produced."* 

159.  But  though  these  mechanical  difficulties  exist 
with  respect  to  printing  from  an  etched  plate,  yet  the 
etching  is  perfect.  The  action  of  the  liberated  elements 
has  produced,  perhaps,  the  most  delicate  piece  of  work- 
manship ever  seen ;  and  though  many  practical  difficul- 
ties will  ever  exist  against  successfully  printing  from 
such  plates,  yet  the  electrotypist  possesses  the  means 
of  multiplying  the  most  faithfully  and  elaborately  ex- 


*  Vide  Proceed.  Elect.  Soc.  p.  98. 
12* 


58 


ELECTROTYPE  MANIPULATION. 


ecuted  among  them,  with  undeviating  certainty;  and  of 
obtaining  in  metal  as  many  perfect  copies  of  the  original 
as  he  may  think  fit  to  take.  "  To  give  an  idea  of  the 
perfect  accuracy  of  these,  I  may  mention  that  in  one  I 
have  taken/ '  writes  Mr.  Grove,  "  on  which  is  a  sign- 
board, measuring  on  the  electrotype  plate  ^th  Dy1  R_ths 
of  an  inch,  jive  lines  of  inscription  can,  with  a  micro- 
scope, be  distinctly  read." 

160.  I  can  conceive,  therefore,  that  among  those  into 
whose  hands  these  pages  may  fall,  there  are  many  who  will 
value  this  discovery,  which  furnishes  a  means  of  multi- 
plying readily  these  treasures  of  art,  I  was  about  to 
say ;  and  possibly  art  is  the  fittest  designation  to  give 
to  this  process,  which  has  arisen  at  the  magic  touch  of 
science.  It  is  true  no  living  artist  can  produce  pencil- 
lings  so  true  and  faithful;  but  science  has  called  into 
action  the  finger  of  nature,  who  is  ever  faithful  and  ever 
true;  and  has  inscribed  upon  her  productions,  not  the 
words  "  drawn  by  Landseer,  and  engraved  by  Cousins," 
but  "  drawn  by  Light,  and  engraved  by  Electricity."* 

161.  M.  Fizeau's  Process. — M.  Fizeau  has  been  most 
successful  in  engraving  Daguerreotypes.  He  inserts  the 
plate  in  a  mixture  of  nitric,  nitrous,  and  hydrochloric 
acids,  by  which  means  the  black  or  silver  parts  of  the 
picture  are  eroded  :  he  then  washes  out  the  chloride  of 
silver  thus  formed  with  ammonia,  and  again  immerses 
the  plate  in  the  acids,  repeating  the  process  several  times. 
A  certain  depth  of  etching  is  thus  produced.    He  then 


*  Vide  Prof.  Grove's  paper. 


ELECTRO-ETCHING. 


59 


rubs  linseed  oil  on  the  plate,  and  washes  it  off,  so  that 
the  parts  in  relief  may  be  still  exposed ;  he  now  gilds 
these  parts  by  the  electro  process,  and  afterwards  re- 
moves the  oil  by  caustic  potash;  this  being  done,  he 
bites  in  the  hollow  parts  with  nitric  acid,  and  so  aug- 
ments the  depth  at  pleasure.  Now,  as  silver  would  soon 
wear  out  in  the  press,  he  coats  the  whole  surface  with 
copper  by  electric  deposition,  and  thus  prepares  the  plate 
for  use;  and  when  one  surface  of  copper  commences  to 
wear,  he  removes  it  by  chemical  means,  and  supplies  its 
place  with  a  fresh  deposit. 

162.  Neio  Mode  of  Etching. — Dr.  Pring  has  de- 
scribed* another  mode  of  etching.  A  polished  steel  or 
other  metal  plate  is  connected  with  the  positive  end  of 
a  series  of  four  or  five,  a  good  coil  of  coated  copper  wire 
being  interposed  between  the  plate  and  the  battery. 
The  other  wire,  guarded  by  glass  or  other  insulator,  is 
held  in  the  hand  and  employed  as  an  etching-tool,  when 
any  device  may  be  drawn.  The  magneto-electric  ma- 
chine will  also  furnish  electricity  for  this  mode.  The 
plate  may  be  reversed  and  connected  with  the  negative 
end  to  vary  the  experiment.  Various  wires  may  be  used. 
No  solution  is  employed ;  it  is  therefore  not  included  in 
our  present  art,  being  mentioned  here  as  a  curious  fact. 


*  Vide  Phil.  Mag.,  Aug.  1843. 


60 


ELECTROTYPE  MANIPULATION. 


IV.  APPLICATIONS  OF  ELECTROTYPE,  &c. 

163.  Patents. — In  reviewing  the  patents  taken  out 
(and  there  are  not  a  few),  I  have  felt  some  degree  of  dif- 
ficulty in  tracing  the  features  by  which  the  right  of  one 
is  distinct  from  the  right  of  another ;  and  have  almost 
doubted  whether  many  of  the  patents  are  not  based 
rather  upon  the  nature  of  the  moulds,  than  of  the  power 
employed.  To  one  is  allowed  the  peculiar  privilege  of 
making  a  wax  model  of  a  stewpan,  and  depositing  cop- 
per upon  this ;  to  another,  the  peculiar  right  of  making 
the  model  of  a  seal  by  uniting  some  printer's  type,  and 
depositing  copper  upon  this.  I  shall  best  succeed  in 
conveying  an  idea  of  the  extent  to  which  this  art  has 
been  patented,  by  extracting  from  the  several  specifi- 
cations the  general  summaries  on  which  the  claims  are 
based.  And  I  doubt  not  that  my  readers  will  be  some- 
what surprised,  when  they  find  how  the  principle  of 
electro-chemical  decomposition — for  it  is  but  a  general 
principle — has  been  seized  upon  and  appropriated. 

164.  One  has  accomplished  certain  "  improvements 
which  have  for  their  object  the  coating  or  covering 
manufactured  articles  composed  of  wrought  or  cast  iron, 
lead  and  copper  and  its  alloys,  with  copper  or  nickel ; 
such  coating  being  effected  by  means  of  galvanic  elec- 
tricity." Nor  does  he  "  confine  himself  to  any  particu- 
lar arrangement  of  apparatus,  but  claims  the  mode  of 
treating  manufactured  articles,  of  the  metal  and  alloys 


APPLICATIONS  OF  ELECTROTYPE. 


61 


above  stated,  so  as  to  obtain  a  permanent  coating  or 
covering  of  copper  or  nickel." 

165.  With  respect  to  plating,  patentees  claim  "  the 
use  of  a  solution*  of  silver,  in  prussiate  of  potash,f  or 
other  analogous  salt,  or  in  pure  ammonia,  in  combina- 
tion with  a  galvanic  current;"  and  "the  use  of  a  solu- 
tion of  silver  in  acid,  so  as  to  constitute  a  neutral  salt, 
in  connection  with  a  galvanic  current ;  the  articles  in 
this  (the  latter)  case  having  been  previously  coated 
with  silver."  Under  the  head  of  gilding,  is  claimed 
"the  use  of  a  solution,  for  the  purpose  of  gilding,  formed 
of  oxide  of  gold,  dissolved  in  prussiate  of  potash  or  soda, 
or  any  other  analogous  salt,  and  combining  the  action 
of  a  galvanic  current  with  the  use  of  a  salt  of  gold  as 
above,  preferring  the  solution  of  gold  formed  by  dissolving 
the  oxide  of  gold  in  prussiate  of  potash ;  and,  further, 
the  patentees  claim,  with  reference  to  the  two  last  heads 
of  their  invention,  the  application  of  a  galvanic  current, 
in  combination  with  solutions  of  gold  or  silver  for 
coating  or  plating  with  gold  or  silver,  whether  the  ar- 
ticles to  be  so  coated  are  formed  entirely  of  metal  or 
only  partly  so." 

166.  The  same  parties  prepare  surfaces  of  iron  to 
receive  a  coating  of  copper  or  other  metal,  by  connect- 
ing them  with  a  piece  of  zinc  and  placing  them  in  acid, 


*  It  is  stated  ' 'that  it  will  be  found  necessary  to  add  from 
time  to  time  a  fresh  supply  of  the  oxide  to  the  solution,  in  order 
that  it  may  be  kept  saturated  with  that  salt." 

f  Or  rather  cyanide  of  potassium.    Vide  §  95. 


62 


ELECTROTYPE  MANIPULATION. 


so  as  to  form  a  voltaic  pair  j  "  after  a  short  time  the 
scales  and  dirt  will  fall  from  the  iron,  leaving  its  sur- 
face perfectly  clean  and  bright and  fit  to  receive  a 
coating  of  copper,  and  then  one  of  silver  or  gold. 

167.  The  right  is  claimed  of  etching  on  iron  or  steel 
by  the  electrolysis  of  a  solution  of  common  salt,  and  an 
iron  or  steel  plate ;  on  silver,  by  a  solution  of  sulphate 
of  soda  or  sulphate  of  silver,  and  a  silver  plate  5  on 
gold,  with  hydrochloric  acid,  and  a  gold  plate ;  on  cop- 
per, sulphate  of  copper  and  a  copper  plate ;  nor  do  the 
patentees  limit  their  claim  to  the  metals  named,  but 
"  claim  the  use  or  application  of  voltaic  electricity  for 
engraving  on  metals  generally f}  and  hence,  I  presume, 
within  this  comprehensive  clause  is  included  the  etch- 
ing of  Daguerreotype  plates  5  although  the  latter  process 
was  not  discovered  until  months  after  the  patent  was 
enrolled. 

168.  Another  application  of  the  art  is  to  form  rollers 
of  copper  for  printing  or  embossing  calicoes,  &c,  by 
making  a  model  of  a  roller,  and,  after  rendering  it  a 
conductor  by  any  of  the  ordinary  means,  depositing  cop- 
per upon  it  j*  also  for  thickening  old  cylinders,  rollers, 
&c,  for  the  same  purpose ;  and  for  filling  up  portions 
of  patterns  that  are  to  be  obliterated. 

169.  Other  applications  of  this  process  are  described  : 
"  1st,  in  the  production  of  a  printing,  embossing,  or 
impressing  metallic  cylinder,  plate,  or  block,  having  a 


*  This  is  merely  a  variation  in  the  form  of  the  mould.' — 
«  163.) 


APPLICATIONS  OF  ELECTROTYPE. 


63 


device  or  pattern  formed  thereon,  suitable  for  the  above 
purposes;  such  device  or  pattern  constituting  one  per- 
feet  or  connected  design,  produced  from  an  originally 
engraved  or  otherwise  executed  portion  of  the  said 
design ;  2d,  in  a  mode  of  joining  together  engraved 
or  otherwise  executed  metallic  plates,  so  as  to  form  one 
connected  surface;  3d,  in  obtaining  an  extended  plain 
surface  to  an  engraved  metallic  plate,  whereon  a  contin- 
uation of,  or  an  addition  to,  the  subject  already  formed 
may  be  engraved ;  4th,  in  certain  modes  of  producing 
suitable  surfaces,  as  aforesaid,  such  modes  not  requiring 
the  ordinary  original  process  of  engraving;*  5th,  in  a 
mode  of  producing  surfaces,  as  aforesaid,  such  surfaces 
being  suitable  for  printing,  or  printing  or  embossing  in 
various  colors  ;f  6th,  in  the  application  and  use  of  dies, 
formed  by  the  agency  of  voltaic  electricity,  for  the  pur- 
pose of  embossing  or  impressing  horn,  hoof,  or  tortoise- 
shell,  in  the  manufacture  of  buttons ;  7th,  in  the  mode 
of  mounting  or  attaching  seals,  bookbinders'  tools, 


*  A  flat  metal  surface  is  covered  with  varnish  ;  the  design 
is  traced  by  removing  the  varnish  ;  the  whole  is  then  covered 
with  plumbago  (§  39),  or  rendered  conductible  by  other  means ; 
and  is  placed  as  a  mould  in  connection  with  the  battery ;  or  a 
lithographic  stone  is  prepared  and  treated  in  a  similar  manner; 
or  the  design  is  punched  in  sheet-lead,  and  this  is  united  to 
other  metal,  and  then  deposited  upon. 

f  Two  or  more  moulds,  according  to  the  number  of  colors, 
are  obtained  from  the  same  original ;  and  from  each  are  re- 
moved those  portions  which  are  not  to  be  printed  by  the  color 
to  which  it  will  be  confined. 


64 


ELECTROTYPE  MANIPULATION. 


or  other  such  instruments  used  for  impressing,  such 
instruments  or  tools  being  produced  by  the  agency 
aforesaid ;  and,  lastly,  in  a  mode  of  producing  seals  for 
impressing  on  wax  or  other  such  substances." 

170.  The  object  of  another  "  invention  is  to  produce 
pipes,  boilers,  stewpans,  or  other  vessels  of  copper, 
through  the  agency  of  voltaic  electricity,"  by  depo- 
siting copper  on  moulds  of  "  clay,  wax,  plaster,  or 
other  like  substances ;  or  of  lead  or  other  metal,  fusible 
at  a  lower  temperature  than  copper."  Another  part  of 
the  invention  relates  to  the  joining  together  of  several 
pieces,  so  as  to  form  vessels ;  and  by  which  means  stop- 
cocks, or  other  such  parts,  may  be  added  to  boilers,  &c, 
formed  by  the  above  process." 

171.  The  above  is  by  no  means  a  complete  abstract 
of  patents,  as  our  readers  will  have  themselves  dis- 
covered from  many  other  processes  that  have  been  pre- 
sented to  them  in  the  course  of  this  work.  But  we 
must  devote  the  space  that  remains,  to  a  few  subjects 
that  have  not  a  place  elsewhere. 

172.  In  the  preceding  pages,  I  have  dwelt  on  the 
copying  of  medals  and  plaster  medallions  alone. 
Enough,  however,  has  been  said  to  render  the  subject 
familiar,  and  to  enable  those  who  are  successful  in  copy- 
ing the  small  objects  here  treated  of,  to  carry  their  ex- 
periments to  any  extent.  Busts,  statues,  vases,  may, 
by  proper  application  of  the  principles  laid  down,  be  as 
readily  coated  with  copper  as  the  small  wax  moulds 
(§  32).  Yea,  almost  anything,  to  which  a  coating  of 
plumbago  can  be  given,  may  serve  as  a  mould  on  which 


CONCLUSION. 


65 


to  deposit  the  metal.  Gutta  percha,  a  new  gum,  which 
becomes  plastic  at  less  than  212°  Fahrenheit,  and  hard- 
ens on  cooling,  will  be  often  found  a  most  convenient 
material  for  moulds  (§42).  With  no  credit  to  my  discern- 
ment, I  could  devise  a  thousand  instances  in  which  this  art 
might  be  available  in  the  common  concerns  of  life  ;  but  I 
had  rather  leave  the  merit  to  him  who  shall  actually  in- 
troduce it  into  these  several  spheres.  It  may  be  found 
available  in  protecting  from  the  effects  of  weather  the 
busts  and  statues  which  are  introduced  in  ornamental 
gardening,  and  which  are  often,  for  the  sake  of  eco- 
nomy, made  of  plaster  of  Paris.  They  may  be  saturated, 
as  described  elsewhere  (§  40),  covered  with  plumbago 
(§  32),  and  placed  within  a  large  vessel  whose  sides  are 
covered  with  copper,  and  then  by  means  which  must 
now  be  familiar  to  the  reader,  a  deposition  of  cop- 
per may  be  formed"  on  them  :  this  can  be  bronzed  by 
the  simple  application  of  the  black-lead  brush  ;  and  thus 
a  sightly  and  permanent  exterior  will  be  produced. — 
By  the  same  means  small  and  valuable  wax  figures  may 
be  preserved  \  the  surfaces  of  these  are  of  themselves 
very  liable  to  crack,  and  fall  off  in  chips.  A  thin  cov- 
ering of  copper,  without  in  the  least  degree  affecting 
the  fineness  of  the  workmanship,  will  preserve  it.  Busts 
and  statues  may  be  made  in  solid  electrotype  metal,  by 
first  coating  a  bust  with  thin  copper,  then  embedding 
the  whole  in  plaster  or  cement,  afterwards  breaking 
away  the  original  bust,  and  finally  making  the  mould 
that  remains  serve  as  a  decomposition  cell. 

173.  Electro-tint,  or  Galvanography. — Another 
13 


66 


ELECTROTYPE  MANIPULATION. 


form  of  deposit  has  been  termed  electro -tint.  It  con- 
sists in  painting  on  white  metal  with  etching-ground  or 
varnish  :  the  several  shades  are  obtained  by  the  relative 
thickness  of  the  layers  of  varnish;  the  whole  is  then  plum- 
bagoed;  and  the  deposit  obtained  on  it  is  used  as  a  plate 
to  furnish  prints.  Prof.  Von  Kobell,  after  obtaining  a 
plate,  examines  a  proof;  and  if  too  faint,  he  makes  a 
mould  of  the  plate;  and  having  obtained  a  deposit, 
which  will  be  similar  to  the  original  painted  plate,  he 
puts  varnish  on  the  parts  which  gave  impressions  too 
pale,  and  obtains  a  second  deposit  on  this,  which  when 
removed  will  give  prints  of  a  better  character. 

174.  Engraved  copper  plates  may  be  readily  multi- 
plied by  electrotype.  The  battery  must  be  in  proportion 
to  the  size  of  the  plate,  and  the  plate  must  be  used  in 
lieu  of  the  moulds.  Sometimes  the  copper  deposit  will 
adhere  so  strongly  as  to  resist  all  attempts  to  remove  it. 
This  may  be  prevented  by  a  very  easy  process. — Before 
the  plate  is  used,  heat  it  and  rub  beeswax  over  the  sur- 
face; continue  the  heat,  and  by  the  application  of  soft 
cotton,  rub  it  perfectly  clean  from  the  wax ;  or  the  plate 
may  be  rubbed  with  black-lead  in  lieu  of  wax.  In  either 
case  it  may  then  be  used  without  fear  of  adhesion.  The 
deposit  obtained  on  it  is  to  be  removed,  and  used  as  a 
mould,  from  which  many  copies  may  be  taken,  equal,  in 
all  points,  to  the  original.  The  engraved  plates  of  the 
recent  Survey  of  London  are  being  thus  multiplied. — 
Sometimes  moulds  of  medals  and  casts  are  made  from 
originals  in  electrotype  copper. 

175.  Glyphography  is  another  application.    A  smooth 


CONCLUSION. 


67 


copper  plate  is  blackened  by  sulphuret  of  potassium, 
and  is  then  coated  with  an  etching-ground,  through 
which  a  design  is  traced.  The  high  lights  are  now 
built  up  of  non-conducting  materials,  so  as  to  prevent 
their  printing-  the  whole  is  coated  with  plumbago, 
and  an  electro-copper  plate  is  formed  from  it :  the  cop- 
per plate  is  afterwards  soldered  on  a  block  of  wood,  and 
is  used  as  a  wood-cut;  it  is  called  an  electro-glyphogra- 
phic  cast  Or  this  plate,  after  etching,  has  a  plaster- 
cast  taken  from  it,  and  from  this  the  high  lights  are  cut 
out ;  it  is  then  oiled,  and  a  second  cast  is  taken,  from 
which  a  stereotype  copy  is  to  be  made.  This  is  called  a 
stereo-glyphographic  cast. 

176.  Metallic  Cloth  is  prepared  by  Messrs.  Elking- 
tons,  for  various  purposes.  On  a  surface  of  copper  is 
attached  very  evenly  stout  linen,  cotton,  or  woollen  cloth; 
the  copper  is  placed  in  a  solution  of  copper,  or  other 
metal,  and  is  connected  with  the  negative  pole  of  the 
battery  :  a  sheet  of  copper,  or  other  metal,  as  the  case 
may  be,  is  placed  opposite,  and  in  connection  with  the 
positive  pole  of  a  battery.  Decomposition  takes  place, 
and  the  metal,  in  endeavoring  to  reach  the  metal  plate, 
insinuates  itself  into  the  interstices  of  the  cloth,  and 
forms  a  perfect  metallic  sheet. 

177.  Purity  of  Sulphuric  Acid. — As  the  great  object 
of  writing  this  treatise  is  to  simplify  the  various  stages 
of  the  process,  I  must  not  leave  unnoticed  a  fact  that 
has  been  pressed  upon  my  attention,  one  which  is  of 
great  practical  importance — the  necessity  of  employing 
pure  sulphuric  acid;  I  mean,  so  far  pure  as  to  be  free 


68 


ELECTROTYPE  MANIPULATION. 


from  nitric  acid.  Very  commonly  a  small  portion  of 
nitric  acid  is  present,  and  this  operates  in  a  most  de- 
structive manner  upon  the  zinc,  defying  all  care  and 
trouble  in  amalgamation ;  for  it  attacks  some  of  the 
mercury,  and  leaves  portions  of  the  zinc  exposed,  giving 
rise  to  an  amount  of  local  action  to  no  trifling  extent ; 
indeed,  it  is  the  serious  objection  to  the  use  of  the  plati- 
nized battery;  and  has  caused  it  to  be  rejected  by  many 
manipulators.  This  will  explain  the  cause  of  amalgama- 
tion's failing,  far  more  effectually  than  the  assumption 
of  the  impurity  of  the  zinc.  The  latter  is  well  con- 
cealed by  the  mercury ;  but  the  nitric  acid  undermines 
the  other  precautionary  means,  and  militates  most  effect- 
ually against  the  permanent  preservation  of  the  zinc. 

178.  Test  for  Nitric  in  Sulphuric  Acid. — The  presence 
of  nitric  acid  may  be  determined  by  the  following 
simple  and  effectual  test  :  Apply  heat  to  a  Florence 
flask,  containing  sulphuric  acid,  with  which  has  been 
mixed  some  sulphate  of  indigo;  should  the  blue  color 
disappear,  nitric  acid  is  present ;  should  it  remain,  the 
acid  is  good  and  fit  for  use. — Besides  exciting  the  bat- 
teries with  the  pure  acid,  it  is  also  requisite  to  employ 
the  same  acid  in  the  process  of  amalgamation.  When 
these  precautions  are  taken,  the  common  rolled  or  cast 
zinc  may  be  employed  with  impunity,  and  a  perfect 
action  will  be  obtained.  It  is  rather  a  difficult  matter 
to  get  rid  of  the  nitric  acid. 

179.  In  reference  to  electrotype  medals  and  other 
works  of  art  produced  in  moulds  taken  from  the  ori- 
ginals, it  may  be  as  well  to  remark  that  there  are  two 


CONCLUSION. 


GO 


methods  of  giving  them  a  silver  or  a  gold  surface  by 
electric  deposition ;  either  by  making  the  medal  ac- 
cording to  the  instructions  given  in  the  First  Part  of 
this  work,  and  then  gilding  or  plating  it )  or  by  pre- 
paring a  good  and  clean  mould  (§  28),  and  depositing 
in  it  a  certain  quantity  of  silver  or  gold,  and  then  back- 
ing it  up  by  the  deposition  of  copper.  The  best  elec- 
trotype medals  are  produced  in  this  way. 

180.  Copying  Busts,  &c. — It  may  not  be  out  of  place 
to  add  here  the  method  pursued  for  copying  busts  or 
statues  from  wax  originals.  The  original  is  covered 
in  the  usual  way  (§  32)  with  plumbago ;  it  is  then 
placed  in  the  copper  solution  of  a  decomposition  cell 
(§  56),  and  is  acted  on  until  a  moderate  coat  of  copper 
is  obtained ;  it  is  now  removed  and  embedded  in  plaster 
of  Paris  \  the  wax  is  melted  out,  and  the  interior  well 
cleaned  with  a  hot  lye  of  potash  or  soda.  It  is  then 
inverted,  and  filled  with  a  solution  of  the  metal  which 
is  to  be  deposited ;  and  in  the  solution  is  placed  a  sheet 
of  the  same  metal,  as  in  the  ordinary  arrangements. 
The  theory  of  this  operation  is  self-evident;  but  in 
practice,  especially  on  small  articles,  a  difficulty  pre- 
sents itself,  to  guard  against  which  requires  no  little 
care.  The  action  occasionally  ceases  without  any  ap- 
parent cause  ;  and  for  days,  although  all  things  seem  in 
order,  no  appreciable  deposit  takes  place.  This  can 
only  be  obviated  by  cleaning  the  positive  metal  and 
greatly  reducing  the  action.  The  effect  is  due  to  phe- 
nomena too  complex  to  be  detailed  in  the  present 
treatise. 

13* 


70 


ELECTROTYPE  MANIPULATION. 


181.  It  is  very  gratifying  to  observe  the  late  import- 
ant applications  of  the  art  that  have  been  made  by  the 
Elkingtons.  Dr.  Braun  has  been  for  some  years  in 
Italy,  and  has  obtained  electrotype  moulds  from  casts  of 
some  of  the  finest  sculptures ;  these  moulds  are  now  the 
property  of  Messrs.  Elkington,  who  intend  to  publish 
copies  obtained  by  their  means ;  and  not  only  so,  their 
intention  is  also  to  multiply  the  choice  works  of  modern 
artists  by  similar  means;  and  thus  to  place  within  the 
reach  of  the  man  of  taste,  at  a  comparatively  moderate 
cost,  faithful  representations  of  the  choicest  works  of 
the  chisel,  which  could  not  otherwise  be  obtained  ex- 
cept at  great  cost,  and  in  the  majority  of  instances 
could  not  be  obtained  at  all. 

The  Messrs.  Elkington  have  already  commenced 
publishing,  on  a  reduced  scale,  genuine  copies  of  por- 
traits of  the  men  of  classic  antiquity,  the  moulds  of 
which  have  been  obtained  from  the  Museo  Borbonico, 
at  Naples,  and  from  the  Lateran  Museum. 

182.  I  have  not  space  to  make  any  lengthened  com- 
ments upon  the  extensive  applications  of  electrotype. 
I  can  fancy  that  scarcely  one  will  read  this  treatise  with 
attention,  and  reflect  on  the  uses  to  which  the  art  has 
been  applied,  without  figuring  to  himself  many  others  to 
which  it  may  be  applied.  The  science  on  which  the 
whole  of  what  we  have  treated  is  based,  reminds  one  of 
that  little  cloud,  dimly  seen  at  first  in  the  distance,  no 
bigger  than  a  man's  hand,  which  gradually  develops 
itself  until  it  enfolds  within  its  spacious  mantle  the 
whole  of  the  visible  face  of  nature.    Every  day  is 


CONCLUSION. 


71 


bringing  fresh  evidence  of  the  vast  extent  of  the  opera- 
tions of  electricity ;  although  each  fresh  acquisition  of 
knowledge  only  teaches  us  how  little  we  really  know. 
Scarcely  do  we  elucidate  one  series  of  problems,  than 
another,  and  another,  and  another,  presents  itself  to  our 
earnest  gaze ;  and  we  are  compelled,  in  summing  up  the 
results  of  even  our  most  successful  labors,  to  confess, 
with  the  great  philosopher,  that  we  are  like  children  on 
the  sea-shore,  who  pick  up  occasionally  one  pebble  of 
greater  value  than  the  rest. 

CHARLES  V.  WALKER. 

Dec.  1,1849. 


INDEX. 


Affinity  for  oxygen  of  positive  copper,  §  94. 
Alkaline  detergent  solutions,  \  119. 
Alloys,  reduction  of,  \  139. 
Amalgamation  to  promote  adhesion,  \  121. 
Applications  of  electro-gilding,  \  135. 

Black  oxide  developed  in  streaks,  \  107. 

Brass,  deposition  of,  f  139. 

Bronze  reduced,  \  139, 

Busts,  mode  of  copying,  \  180. 

Button-dies,  manufacture  of,  \  169. 

Cleaning  electro-plate,  §  123. 
Cleansing,  great  importance  of,  §116. 
Cleansing  by  the  dry  method,  g  118. 
Cleansing  by  the  wet  method,  $  119. 
Coating  metals  with  copper  and  nickel,  £  164. 
Colors,  blocks  for  printing,  produced,  $  169. 
Cyanide  of  potassium,  electrolysis  of,  \  94. 
 preparation  of,  \  95. 

Daguerreotype,  electro-etching  of,  $  153. 

 pictures,  nature  of,  \  155. 

 protected  by  electro-gilding,  \  136. 

 plates,  I  137. 


74 


INDEX. 


Electro-etching,  §  149. 
Electro-etching,  new  mode  of,  \  162. 
Electro-extension  of  plates,  &c,  \  169. 
Electro-gilding,  first  case  of,  §  92. 
Electrolytic  action,  principles  of,  §  94. 

 copies  of  Daguerreotypes,  \  137. 

Electro-plating,  early  instance  of,  \  92. 
Electro-tint,  \  173. 
Electro-uniting  of  boilers,  &c,  \  170. 
Electro-uniting  of  plates,  &c,  \  169. 
Engraving,  manual  labor  of,  saved,  \  169. 
Etching-ground  of  gold,  \  135. 
  plates,  patent  for,  \  167. 

Film  of  air  on  all  bodies,  \  120. 

Fused  compounds  electrolyzed,  \\  140,  142. 

Galvanography,  \  173. 
Gilding  by  a  single  cell,  |  108. 

 battery  process,  §  111. 

 patent  for,  g  165. 

Gilding-wax,  \  124. 

Gilding  with  the  battery,  advantages  of,  \  110. 
Gold  solution,  composition  of,  \  99. 
Gutta-percha  moulds,  \  172. 

Heat  for  preparing  metallic  surfaces,  $  114. 
Homogeneity  of  silver,  how  to  obtain,  $  158,  note. 
Hydrochloric  acid,  electrolysis  of,  §  158. 
Hydrogen  adheres  to  plates,  \  156. 

Iron  surfaces  cleaned  by  voltaic  action,  \  166. 

Lead,  deposition  of,  \  128. 


INDEX. 


Magneto-electro  plating,  §  144. 

Metallic  cloth,  §  176. 

Metallic  solutions,  various,  §  125,  &c. 

Metallo-chromes,  $  145. 

Motion  to  articles  while  plating,  \  115. 

Nitrate  of  silver,  experiment  with,  §  92. 

Nitric  acid,  &c,  for  preparing  metallic  surfaces,  \  119. 

 ,  test  for,  I  178. 

Ore,  reduction  of,  H  141,  143. 
Oxide  of  lead  deposited,  g  147. 
Oxide  of  iron  deposited,  \  148. 
Oxides  of  silver  and  gold,  \\  97,  99. 

Patents,  summary  of,  §  163,  &c. 

Patterns  for  printing,  &c,  produced,  $  169. 

Platinating,  \\  128,  129. 

Plating  by  single  cell  process,  §  106. 

 the  battery  process,  §  111. 

 ,  patent  for,  J  165. 

Primary  results,  definition  of,  §  94. 
Purity  of  sulphuric  acid,  \  177. 

Relation  in  size  between  plates  of  elementary  pairs,  $  157. 

Salts  of  gold  and  silver  easily  decomposed,  g  104. 

Sawdust,  hot,  for  drying  cleaned  articles,  \  120. 

Scratch-brush,  its  value,  \  121. 

Seals,  mounting  by  electrotype,  g  169. 

Secondary  results,  nature  of,  f  94. 

Secondary  current,  \  112. 

Silver  solution,  composition  of,  \  96. 

Single  cell,  flat,  for  gilding,  &c,  \  105. 

Size  of  generating  pairs  in  relation  to  electrodes,  $  157. 


76 


INDEX. 


Soap-bubble,  J  146,  note. 
Statues,  mode  of  copying,  J  180. 

Tarnished  silver,  mode  of  cleaning,  \  123. 
Theory  of  electrolysis,  §  94,  &c. 
Thin  wire  for  retarding  the  action,  §  106,  note. 
Tin,  deposition  of,  \  128. 

Union  between  copper  and  gold  or  silver,  mode  of  producing, 
I  116,  &c. 

Vessels  of  capacity  formed,  \  170. 
Voltaic  condenser,  §  112. 
Voltaic  governor,  §  107. 

Whole  designs  produced  by  the  electro-union  of  parts,  $  169. 
Zinc,  deposition  of,  \\  128,  138. 


THE  END. 


PUBLICATIONS 


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naces, Casting  and  Founding  with  Metallic  Moulds,  Joining  and  Working  Sheet 
Metal.  Peculiarities  of  the  different  Tools  employed.  Processes  dependent  on 
the  ductility  of  Metals.  Wire  Drawing,  Drawing  Metal  Tubes,  Soldering.  The 
use  of  the  Blowpipe,  and  every  other  known  Metal- Worker's  Tool.  To  tho 
works  of  Holtzappfel,  Oliver  Byrne  has  added  all  that  is  useful  and  peculiar 
lo  the  American  Metal- Worker. 


3 


THE  MANUFACTURE  OF  IRON  IN  ALL  ITS 
VARIOUS  BRANCHES: 

To  which  is  added  an  Essay  on  the  Manufacture  of  Steel,  by 
Frederick  Overman,  Mining  Engineer,  with  one  hundred  and 
fifty  Wood  Engravings.  A  new  edition.  In  One  Volume,  oc- 
tavo, five  hundred  pages  $5.00 

We  have  now  to  announce  the  appearance  of  another  valuable  work  on  the 
subject  which,  in  our  humble  opinion,  supplies  any  deficiency  which  late  im- 
provements and  discoveries  may  have  caused,  from  the  lapse  of  time  since  the 
date  of  "•  Mushet"  and  "  Schrivenor."  It  is  the  production  of  one  of  our  trans- 
atlantic brethren,  Mr.  Frederick  Overman,  Mining  Engineer;  and  we  do  not 
hesitate  to  set  it  down  as  a  work  of  great  importance  to  all  connected  with  the 
iron  interest;  one  which,  while  it  is  sufficiently  technological  fully  to  explain 
chemical  analysis,  and  the  various  phenomena  of  iron  under  different  circum- 
stances, to  the  satisfaction  of  the  most  fastidious,  is  written  in  that  clear  and 
comprehensive  style  as  to  be  available  to  the  capacity  of  the  humblest  mind, 
and  consequently  will  be  of  much  advantage  to  those  works  where  the  proprie- 
tors may  see  the  desirability  of  placing  it  in  the  hands  of  their  operatives. — 
London  Morning  Journal. 


A  TREATISE  ON  THE  AMERICAN  STEAM-ENGINE. 

Illustrated  by  numerous  Wood  Cuts  and  other  Engravings. 
By  Oliver  Byrne.    In  One  Volume.  (In  press.) 


PROPELLERS  AND  STEAM  NAVIGATION: 

With  Biographical  Sketches  of  Early  Inventors.  By  Robert 
Macfarlane,  C.  E.,  Editor  of  the  "  Scientific  American."  In 
One  Volume,  12mo.  Illustrated  by  over  Eighty  Wood  Engrav- 
ings  75  cts. 

The  object  of  this  "  History  of  Propellers  and  Steam  Navigation"  is  twofold. 
One  is  the  arrangement  and  description  of  many  devices  which  have  been  in- 
vented to  propel  vessels,  in  order  to  prevent  many  ingenious  men  from  wasting 
their  time,  talents,  and  money  on  such  projects.  The  immense  amount  of  time, 
study,  and  money  thrown  away  on  such  contrivances  is  beyond  calculation. 
In  this  respect,  it  is  hoped  that  it  will  be  the  means  of  doing  some  good. — 
Preface. 


A  TREATISE  ON  SCREW-PROPELLERS  AND 
THEIR  STEAM-ENGINES. 

With  Practical  Rules  and  Examples  by  which  to  Calculate 
and  Construct  the  same  for  any  description  of  Vessels.  By  J. 
W.  Nystrom.  Illustrated  by  twenty-five  large  working  Draw- 
ings.   In  one  Volume,  octavo. 


4 


PRACTICAL  SERIES. 


THE  AMEBIC  AN  MILLER  AND  MILLWRIGHT'S  ASSIST- 
ANT.  $1. 

THE  TURNER'S  COMPANION.    75  cts. 

THE  PAINTER,  GILDER,  AND  VARNISHER'S  COMPA- 
NION.   75  cts. 

THE  DYER  AND  COLOUR-MAKER'S  COMPANION.  75  cts. 
THE  BUILDER'S  COMPANION.  $1. 
THE  CABINET-MAKER'S  COMPANION.    75  cts. 
A  TREATISE  ON  A  BOX  OF  INSTRUMENTS.    By  Thomas 
Kentish.  $1. 

THE  PAPER-HANGER'S  COMPANION.  By  J.  Arrowsmith. 
75  cts. 

THE  ASSAYER'S  GUIDE.    By  Oscar  M.  Lieber.   75  cts. 
THE  COMPLETE  PRACTICAL  BREWER.  ByM.  L.  Byrn.  $1. 
THE  COMPLETE  PRACTICAL  DISTILLER.  ByM.  L.  Byrn.  $1. 
THE  BOOKBINDER'S  MANUAL. 

THE  PYROTECHNIST'S  COMPANION.  By  G.  W.  Morti- 
mer.   75  cts. 

WALKER'S  ELECTROTYPE  MANIPULATION.    75  cts. 


THE  AMERICAN  MILLER  AND  MILLWRIGHT'S 
ASSISTANT: 

By  William  Carter  Hughes,  Editor  of  "  The  American  Mil- 
ler," (newspaper,)  Buffalo,  N.  Y.  Illustrated  by  Drawings  of 
the  most  approved  Machinery.    In  One  Volume,  12mo  $1 

The  author  offers  it  as  a  substantial  reference,  instead  of  speculative  theories, 
which  belong  only  to  those  not  immediately  attached  to  the  business.  Special 
notice  is  also  given  of  most  of  the  essential  improvements  which  have  of  late 
been  introduced  for  the  benefit  of  the  Miller. — Savannah  Republican. 

The  whole  business  of  making  flour  is  most  thoroughly  treated  by  him. — 
Bulletin. 

A  very  comprehensive  view  of  the  Millwright's  business. — Southern  Literary 
Messenger. 


THE  TURNER'S  COMPANION: 

Containing  Instructions  in  Concentric,  Elliptic,  and  Eccentric 
Turning.  Also,  various  Plates  of  Chucks,  Tools,  and  Instru- 
ments, and  Directions  for  using  the  Eccentric  Cutter,  Drill, 
Vertical  Cutter,  and  Circular  Best ;  with  Patterns  and  Instruc- 
tions for  working  them.  Illustrated  by  numerous  Engravings. 
In  One  Volume,  12mo  75  cts. 

The  object  of  the  Turner's  Companion  is  to  explain  in  a  clear,  concise,  and 
intelligible  manner,  the  rudiments  of  this  beautiful  art.— Savannah  Republican. 

There  is  no  description  of  turning  or  lathe-work  that  this  elegant  little  treatise 
does  not  describe  and  illustrate. —  Western  Lit.  Messenger. 


5 


THE  PAINTER,  GILDER,  AND  VARNISHER'S 

COMPANION: 

Containing  Rules  and  Regulations  for  every  thing  relating  to 
the  arts  of  Painting,  Gilding,  Varnishing,  and  Glass  Staining ; 
numerous  useful  and  valuable  Receipts  ;  Tests  for  the  detection 
of  Adulterations  in  Oils,  Colours,  &c,  and  a  Statement  of  the 
Diseases  and  Accidents  to  which  Painters,  Gilders,  and  Var- 
nishers  are  particularly  liable ;  with  the  simplest  methods  of 
Prevention  and  Remedy.  In  one  vol.  small  12mo.,  cloth.  75cts. 

Rejecting  all  that  appeared  foreign  to  the  subject,  the  compiler  has  omitted 
nothing  of  real  practical  worth. — Hunt's  Merchant's  Magazine. 

An  excellent  practical  work,  and  one  which  the  practical  man  cannot  afford 
to  be  without. — Farmer  and  Mechanic. 

It  contains  every  thing  that  is  of  interest  to  persons  engaged  in  this  trade. 
— Bulletin. 

This  book  will  prove  valuable  to  all  whose  business  is  in  any  way  connected 
with  painting. — ScoWs  Weekly. 
Cannot  fail  to  be  useful. — JV.  Y.  Commercial. 


THE  BUILDER'S  POCKET  COMPANION: 

Containing  the  Elements  of  Building,  Surveying,  and  Archi- 
tecture ;  with  Practical  Rules  and  Instructions  connected  with 
the  subject.  By  A.  C.  Smeaton,  Civil  Engineer,  &c.  In  one 
volume,  12mo.  $1. 

Contents: — The  Builder,  Carpenter,  Joiner,  Mason,  Plas- 
terer, Plumber,  Painter,  Smith,  Practical  Geometry,  Surveyor, 
Cohesive  Strength  of  Bodies,  Architect. 

It  gives,  in  a  small  space,  the  most  thorough  directions  to  the  builder,  from 
the  laying  of  a  brick,  or  the  felling  of  a  tree,  up  to  the  most  elaborate  pro- 
duction of  ornamental  architecture.  It  is  scientific,  without  being  obscure  and 
unintelligible,  and  every  house-carpenter,  master,  journeyman,  or  apprentice, 
should  have  a  copy  at  hand  always. — Evening  Bulletin. 

Complete  on  the  subjects  of  which  it  treats.  A  most  useful  practical  work. 
— Bait.  American. 

It  must  be  of  great  practical  utility. —  Savannah  Republican. 

To  whatever  branch  of  the  art  of  building  the  reader  may  belong,  he  will 
find  in  this  something  valuable  and  calculated  to  assist  his  progress. — Farmer 
and  Mechanic. 

This  is  a  valuable  little  volume,  designed  to  assist  the  student  in  the  acquisi- 
tion of  elementary  knowledge,  and  will  be  found  highly  advantageous  to  every 
young  man  who  has  devoted  himself  to  the  interesting  pursuits'  of  which  it 
treats. — Yd.  Herald. 

1* 


0 


THE  DYER  AND  COLOUR-MAKER'S  COM- 
PANION : 

Containing  upwards  of  two  hundred  Receipts  for  making  Co- 
lors, on  the  most  approved  principles,  for  all  the  various  styles 
and  fabrics  now  in  existence ;  with  the  Scouring  Process,  and 
plain  Directions  for  Preparing,  Washing-off,  and  Finishing  the 
Goods.    In  one  volume,  small  12mo.,  cloth.    75  cts. 

This  is  another  of  that  most  excellent  class  of  practical  hooks,  which  the 
publisher  is  giving  to  the  public.  Indeed  we  believe  there  is  not,  for  manu- 
facturers, a  more  valuable  work,  having  been  prepared  for,  and  expressly 
adapted  to  their  business. — Farmer  and  Mechanic. 

It  is  a  valuable  book.— Otsego  Republican. 

We  have  shown  it  to  some  practical  men,  who  all  pronounced  it  the  completest 
thing  of  the  kind  they  had  seen — N.  Y.  Nation. 


THE  CABINET-MAKER  AND  UPHOLSTERER'S 
COMPANION: 

Comprising  the  Rudiments  and  Principles  of  Cabinet  Making 
and  Upholstery,  with  familiar  instructions,  illustrated  by  Ex- 
amples, for  attaining  a  proficiency  in  the  Art  of  Drawing,  as 
applicable  to  Cabinet  Work ;  the  processes  of  Veneering,  Inlay- 
ing, and  Buhl  Work;  the  art  of  Dyeing  and  Staining  Wood, 
Ivory,  Bone,  Tortoise-shell,  etc.  Directions  for  Lackering,  Ja- 
panning, and  Varnishing ;  to  make  French  Polish ;  to  prepare 
the  best  Glues,  Cements,  and  Compositions,  and  a  number  of 
Receipts  particularly  useful  for  Workmen  generally,  with  Ex- 
planatory and  Illustrative  Engravings.  By  J.  Stokes.  In  one 
volume,  12mo.,  with  illustrations.   Second  Edition.  75  cts. 


THE  PAPER-HANGER'S  COMPANION: 

In  which  the  Practical  Operations  of  the  Trade  are  system- 
atically laid  down ;  with  copious  Directions  Preparatory  to  Pa- 
pering ;  Preventions  against  the  effect  of  Damp  in  Walls ;  the 
various  Cements  and  Pastes  adapted  to  the  several  purposes  of 
the  Trade ;  Observations  and  Directions  for  the  Panelling  and 
Ornamenting  of  Rooms,  &c.  &c.  By  James  Arrowsmith.  In 
One  Volume,  12mo.    75  cts. 


THE  ANALYTICAL  CHEMIST'S  ASSISTANT: 

A.  Manual  of  Chemical  Analysis,  botli  Qualitative  and  Quan- 
titative, of  Natural  and  Artificial  Inorganic  Compounds ;  to 
which  are  appended  the  Rules  for  Detecting  Arsenic  in  a  Case 
of  Poisoning.  By  Frederik  Wo:hler,  Professor  of  Chemistry 
in  the  University  of  Gottingen.  Translated  from  the  German, 
with  an  Introduction,  Illustrations,  and  copious  Additions,  by 
Oscar  M.  Lieber,  Author  of  the  "Assayer's  Guide."  In  one 
Volume,  12mo.  $1.25. 


RURAL  CHEMISTRY: 

An  Elementary  Introduction  to  the  Study  of  the  Science,  in 
its  relation  to  Agriculture  and  the  Arts  of  Life.  By  Edward 
Solley,  Professor  of  Chemistry  in  the  Horticultural  Society 
of  London.  From  the  Third  Improved  London  Edition.  12mo. 
$1.25.   

THE  FRUIT,  FLOWER,  AND  KITCHEN  GARDEN. 

By  Patrick  Neill,  L.  L.  D. 
Thoroughly  revised,  and  adapted  to  the  climate  and  seasons 
of  the  United  States,  by  a  Practical  Horticulturist.  Illustrated 
by  numerous  Engravings.    In  one  volume,  12mo.  $1.25. 


HOUSEHOLD  SURGERY;  OR,  HINTS  ON  EMER- 
GENCIES. 

By  J.  F.  South,  one  of  the  Surgeons  of  St.  Thomas's  Hos- 
pital. In  one  volume,  12mo.  Illustrated  by  nearly  fifty  En- 
gravings. $1.25. 


HOUSEHOLD  MEDICINE. 

In  one  volume,  12mo.  Uniform  with,  and  a  companion  to, 
the  above.    (In  immediate  preparation.) 


8 


THE  COMPLETE  PRACTICAL  BREWER; 

Or,  Plain,  Concise,  and  Accurate  Instructions  in  the  Art  of 
Brewing  Beer,  Ale,  Porter,  &c.  &c,  and  the  Process  of  Making 
all  the  Small  Beers.  By  M.  Lafayette  Byrn,  M.  D.  With 
Illustrations,  12mo.  $1. 


THE  COMPLETE  PRACTICAL  DISTILLER; 

By  M.  Lafayette  Byrn,  M.  D.  With  Illustrations,  12mo.  $1. 


THE  ENCYCLOPEDIA  OF  CHEMISTRY,  PRACTI- 
CAL AND  THEORETICAL : 

Embracing  its  application  to  the  Arts,  Metallurgy,  Mineralogy, 
Geology,  Medicine,  and  Pharmacy.  By  James  C.  Booth,  Melter 
and  Refiner  in  the  United  States  Mint ;  Professor  of  Applied 
Chemistry  in  the  Franklin  Institute,  etc.;  assisted  by  Campbell 
Morfit,  author  of  "Chemical  Manipulations,"  etc.  Complete 
in  one  volume,  royal  octavo,  978  pages,  with  numerous  wood 
cuts  and  other  illustrations.  $5. 

It  covers  the  whole  field  of  Chemistry  as  applied  to  Arts  and  Sciences.  *  *  * 
As  no  library  is  complete  without  a  common  dictionary,  it  is  also  our  opinion 
that  none  can  be  without  this  Encyclopedia  of  Chemistry. — Scientific  American. 

A  work  of  time  and  labour,  and  a  treasury  of  chemical  information. — North 
American. 

By  far  the  best  manual  of  the  kind  which  has  been  presented  to  the  Ameri- 
can public. — Boston  Courier. 


PERFUMERY;  ITS  MANUFACTURE  AND  USE: 

With  Instructions  in  every  branch  of  the  Art,  and  Receipts 
for  all  the  Fashionable  Preparations  ;  the  whole  forming  a  valu- 
able aid  to  the  Perfumer,  Druggist,  and  Soap  Manufacturer. 
Illustrated  by  numerous  Wood-cuts.  From  the  French  of  Cel- 
nart,  and  other  late  authorities.  With  Additions  and  Improve- 
ments by  Campbell  Morfit,  one  of  the  Editors  of  the  "  Ency- 
clopedia of  Chemistry."    In  one  volume,  12mo.,  cloth.  $1. 


9 


A  TREATISE  ON  A  BOX  OF  INSTRUMENTS, 

And  the  Slide  Rule,  with  the  Theory  of  Trigonometry  and 
Logarithms,  including  Practical  Geometry,  Surveying,  Measur- 
ing of  Timber,  Cask  and  Malt  Gauging,  Heights  and  Distances. 
By  Thomas  Kentish.    In  One  Volume,  12mo.  $1. 


STEAM  FOR  THE  MILLION. 

An  Elementary  Outline  Treatise  on  the  Nature  and  Manage- 
ment of  Steam,  and  the  Principles  and  Arrangement  of  the 
Engine.  Adapted  for  Popular  Instruction,  for  Apprentices,  and 
for  the  use  of  the  Navigator.  With  an  Appendix  containing 
Notes  on  Expansive  Steam,  &c.    In  One  Volume,  8vo...37^- cts. 


SYLLABUS  OF  A  COMPLETE  COURSE  OF  LEC- 
TURES ON  CHEMISTRY: 

Including  its  Application  to  the  Arts,  Agriculture,  and  Mining, 
prepared  for  the  use  of  the  Gentlemen  Cadets  at  the  Hon.  E.  I. 
Co.'s  Military  Seminary,  Addiscombe.  By  Professor  E.  Solly, 
Lecturer  on  Chemistry  in  the  Hon.  E.  I.  Co.'s  Military  Seminary. 
Revised  by  the  Author  of  "  Chemical  Manipulations."  In  one 
volume,  octavo,  cloth.  $1.25. 


THE  ASSAYER'S  GUIDE; 

Or,  Practical  Directions  to  Assayers,  Miners,  and  Smelters, 
for  the  Tests  and  Assays,  by  Heat  and  by  Wet  Processes,  of  the 
Ores  of  all  the  principal  Metals,  and  of  Gold  and  Silver  Coins 
and  Alloys.  By  Oscar  M.  Lieber,  late  Geologist  to  the  State 
of  Mississippi.    l'2mo.   With  Illustrations.   75  cts. 


THE  BOOKBINDER'S  MANUAL. 

Complete  in  one  Volume,  12mo. 


10 


ELECTROTYPE  MANIPULATION: 

Being  the  Theory  and  Plain  Instructions  in  the  Art  of  Working 
in  Metals,  by  Precipitating  them  from  their  Solutions,  through 
the  agency  of  Galvanic  or  Voltaic  Electricity.  By  Charles  V. 
Walker,  Hon.  Secretary  to  the  London  Electrical  Society,  etc 
Illustrated  by  Wood-cuts.  A  New  Edition,  from  the  Twenty- 
fifth  London  Edition.    12mo.    75  cts. 


PHOTOGENIC  MANIPULATION: 

Containing  the  Theory  and  Plain  Instructions  in  the  Art  of 
Photography,  or  the  Productions  of  Pictures  through  the  Agency 
of  Light  ;  including  Calotype,  Chrysotype,  Cyanotype,  Chroma- 
type,  Energiatype,  Anthotype,  Amphitype,  Daguerreotype, 
Thermography,  Electrical  and  Galvanic  Impressions.  By 
George  Thomas  Fisher,  Jr.,  Assistant  in  the  Laboratory  of 
the  London  Institution.  Illustrated  by  wood-cuts.  In  one  vo- 
lume, 24mo.,  cloth.    62  cts. 


MATHEMATICS  EOS  PRACTICAL  MEN : 

Being  a  Common-Place  Book  of  Principles,  Theorems,  Rules, 
and  Tables,  in  various  departments  of  Pure  and  Mixed  Mathe- 
matics, with  their  Applications ;  especially  to  the  pursuits  of 
Surveyors,  Architects,  Mechanics,  and  Civil  Engineers,  with  nu- 
merous Engravings.  By  Olinthus  Gregory,  L.  L.  D.  $1.50. 

Only  let  men  awake,  and  fix  their  eyes,  one  while  on  the  nature  of  things, 
another  while  on  the  application  of  them  to  the  use  and  service  of  mankind. 
— Lord  Bacon. 


ELEMENTARY  COURSE  OF  INSTRUCTION  ON 
ORDNANCE,  GUNNERY,  AND  STEAM; 

Prepared  for  the  use  of  the  Midshipmen  at  the  Naval  School. 
By  James  H.  Wakd,  U.  S.  N.    In  one  Volume,  octavo.  $2.50. 


11 


SHEEP-HUSBANDRY  IK  THE  SOUTH: 

Comprising  a  Treatise  on  the  Acclimation  of  Sheep  in  the 
Southern  States,  and  an  Account  of  the  different  Breeds.  Also, 
a  Complete  Manual  of  Breeding,  Summer  and  Winter  Manage- 
ment, and  of  the  Treatment  of  Diseases.  With  Portraits  and 
other  Illustrations.  By  Henry  S.  Randall.  In  One  Volume, 
octavo  $1.25 


ELWOOD'S  GRAIN  TABLES: 

"  Showing  the  value  of  Bushels  and  Pounds  of  different  kinds 
of  Grain,  calculated  in  Federal  Money,  so  arranged  as  to  exhibit 
upon  a  single  page  the  value  at  a  given  price  from  ten  cents  to  two 
dollars  per  bushel,  of  any  quantity  from  one  pound  to  ten  thousand 
bushels.  By  J.  L.  Elwood.  A  new  Edition.  In  One  Volume, 
12mo  $1 

To  Millers  and  Produce  Dealers  this  work  is  pronounced  by  all  who  have  it 
in  use,  to  be  superior  in  arrangement  to  any  work  of  the  kind  published — and 
unerring  accuracy  in  every  calculation  may  be  relied  upon  in  every  instance. 

4®="  A  reward  of  Twenty-five  Dollars  is  offered  for  an  error  of  one  cent  found 
in  the  work. 


MISS  LESLIE'S  COMPLETE  COOKERY. 

Directions  for  Cookery,  in  its  Various  Branches.  By  Miss 
Leslie.  Forty-second  Edition.  Thoroughly  Revised,  with  the 
Addition  of  New  Receipts.  In  One  Volume,  12mo,  half  bound, 
or  in  sheep  $1 

In  preparing  a  new  and  carefully  revised  edition  of  this  my  first  work  on 
cookery,  I  have  introduced  improvements,  corrected  errors,  and  added  new 
receipts,  that  I  trust  will  on  trial  be  found  satisfactory.  The  success  of  the 
book  (proved  by  its  immense  and  increasing  circulation)  affords  conclusive  evi- 
dence that  it  has  obtained  the  approbation  of  a  large  number  of  my  country- 
women; many  of  whom  have  informed  me  that  it  has  made  practical  house- 
wives of  young  ladies  who  have  entered  into  married  life  with  no  other  acquire- 
ments than  a  few  showy  accomplishments.  Gentlemen,  also,  have  told  me  of 
great  improvements  in  the  family  table,  after  presenting  their  wives  with  this 
manual  of  domestic  cookery,  and  that,  after  a  morning  devoted  to  the  fatigues 
of  business,  they  no  longer  find  themselves  subjected  to  the  annoyance  of  an 
ill-dressed  dinner. — Preface, 


MISS  LESLIE'S  TWO  HUNDRED  RECEIPTS  IN 
FRENCH  COOKERY. 


A  new  Edition,  in  cloth 


25  cts. 


12 


TABLES  OF  LOGARITHMS  FOR  ENGINEERS  AND 
MACHINISTS : 

Containing  the  Logarithms  of  the  Natural  Numbers,  from  1  to 
*00000,  by  the  help  of  Proportional  Differences.  And  Loga- 
rithmic Sines,  Cosines,  Tangents,  Co-tangents,  Secants,  and  Co- 
secants, for  every  Degree  and  Minute  in  the  Quadrant.  To 
which  are  added,  Differences  for  every  100  Seconds.  By  Oliver 
Byrne,  Civil,  Military,  and  Mechanical  Engineer.  In  One 
Volume,  8vo.  cloth  ,  $1 


TWO  HUNDRED  DESIGNS  FOR  COTTAGES  AND 
VILLAS,  &c.  &c. 

Original  and  Selected.  By  Thomas  U.  Walter,  Architect  of 
Girard  College,  and  John  Jay  Smith,  Librarian  of  the  Phila- 
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13 


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14 


THE  POETICAL  WORKS  OF  THOMAS  GRAY: 

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15 


THE  FEMALE  POETS  OF  GREAT  BRITAIN. 

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Hunt's  Merchants'1  Magazine,. 


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16 

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17 


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22 


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l 


